Feng Hong (Chinese: 馮弘; died 438), courtesy name Wentong (文通), also known by his posthumous name as the Emperor Zhaocheng of Northern Yan (北燕昭成帝), was the last monarch of the Chinese Northern Yan dynasty. He seized the throne in 430 when his brother Feng Ba (Emperor Wencheng) was ill, and he used the title "Heavenly King". During his reign, the Northern Yan grew increasingly smaller and weaker in light of repeated attacks by rival Northern Wei dynasty, and in 436 he evacuated his state and fled to Goguryeo, ending the Northern Yan. Once in Goguryeo, however, he assumed the role of Goguryeo's suzerain (a status he had claimed earlier). King Jangsu of Goguryeo, unable to stand Feng Hong's antics, killed him in 438 although he gave Feng Hong a posthumous name.

It is not known when Feng Hong was born, but it is known that he was Feng Ba's younger brother. There was no historical record about him until 407, after his brother Feng Ba (along with another brother, Feng Sufu (馮素弗), as long as others) had overthrown the tyrannical Later Yan emperor Murong Xi and made Murong Xi's adoptive nephew Murong Yun emperor. (Murong Yun, who soon changed his name back to the original Gao Yun, is regarded by some as the last emperor of Later Yan and by some as the first emperor of Northern Yan.) Late in 407, Gao Yun commissioned Feng Hong as a major general. Probably also at the same time (but definitely during Gao Yun's reign), Feng Hong was created the Duke of Ji.

After Gao Yun was assassinated by his attendants Li Ban (離班) and Tao Ren (桃仁) in 409, the officials of the regime supported Feng Ba as the new emperor. Feng Ba, when he took the throne, gave a promotion to Feng Hong, but continued to let him carry the title of Duke of Ji.

In 410, Feng Ba's cousin Feng Wani (馮萬泥) and another cousin's son Feng Ruchen (馮乳陳) both felt that they contributed much to Feng Ba's success, and therefore were resentful that they were not at Longcheng and in control of the imperial government but were required to serve as commanding generals at the cities of Feiru (肥如, in modern Qinhuangdao, Hebei) and Bailang (白狼, in modern Zhaoyang, Liaoning). They therefore rose in rebellion together. Feng Ba sent Feng Hong and Zhang Xing to attack them, and after they were defeated by Feng Hong and Zhang, they surrendered, but Feng Hong executed them regardless. After this incident, Feng Ba created him the Duke of Zhongshan.

Little is known about Feng Hong's actions during most of Feng Ba's reign, other than that he appeared to have remained in powerful positions, and by 430 he was Feng Ba's prime minister. That year, Feng Ba was seriously ill, and he issued an edict transferring his authorities to his crown prince Feng Yi (馮翼). However, Feng Ba's favorite concubine Consort Song wanted to have her son Feng Shouju (馮受居) inherit the throne, and therefore told Feng Yi that Feng Ba would soon recover and that he should not be so anxious to take over authority; Feng Yi agreed and retreated to his palace. Consort Song then falsely issued orders in Feng Ba's name cutting off communications with the outside, and Feng Yi and Feng Ba's other sons, as well as imperial officials, were not allowed to see Feng Ba. Only one of her trusted officials, Hu Fu (胡福), was able to enter the palace to be in charge of security. However, Hu was secretly resentful of Consort Song's ambitions, and he informed Feng Hong of her intentions. Feng Hong immediately attacked the palace and seized control of it. Feng Ba, hearing up this, died in shock. Feng Hong then took the throne himself and, after defeating Feng Yi's troops, slaughtered all of Feng Ba's sons. He used the title "Heavenly King" (Tian Wang).

What appeared evidence late in Feng Ba's reign, but even more so in Feng Hong's reign, were incessant attacks by the neighboring rival Northern Wei. This appeared to be particularly true after Northern Wei annexed all of the territory of Xia in 431 and therefore no longer had a major western rival to deal with. Emperor Taiwu of Northern Wei made periodic attacks to pillage Northern Yan territory and then withdraw, draining Northern Yan of food supplies and other resources and weakening it.

While Feng Hong was the Duke of Zhongshan, his wife was Lady Wang, who bore him at least three sons, Feng Chong (馮崇), Feng Lang (馮朗), and Feng Miao (馮邈), and Feng Chong was his oldest son. However, in 431, Feng Hong created Lady Murong princess instead, and in 432, he created Princess Murong's son Feng Wangren (馮王仁) crown prince.

In fall 432, Northern Wei's Emperor Taiwu made the first major attack of Feng Hong's reign, heading for Northern Yan's capital Helong (和龍, in modern Jinzhou, Liaoning). Feng Hong tried to appease the Northern Wei emperor by delivering gifts of beef and wine to his army, to no avail. 10 Northern Yan commanderies surrendered to Northern Wei, and Northern Wei forces captured a number of Northern Yan cities and put Helong under siege. However, two months later, Emperor Taiwu withdrew after capturing 30,000 households from Northern Yan and relocating them to his You Province (幽州, modern Beijing, Tianjin, and northern Hebei). Feng Hong's official Guo Yuan (郭淵) suggested to Feng Hong that he offer to be a Northern Wei vassal and send a daughter to be Emperor Taiwu's consort, but Feng Hong refused, stating that the enmity between the states were so deep that he would be killed anyway even if he surrendered. (While Northern Wei was sieging Helong, the Northern Wei general Zhu Xiuzhi (朱脩之), who had been captured from Liu Song, plotted to assassinate Emperor Taiwu and then join Feng Hong, but his plot was discovered, and he fled to Feng Hong, who in turn sent him back to Liu Song, seeking Liu Song aid. Henceforth, Liu Song and Northern Yan were informal allies, although Liu Song provided little actual help.)