The Promise of Chang'an (Chinese: 长安诺; pinyin: Cháng'ān Nuò) is a 2019-20 Chinese television series directed by Yin Tao, starred by Cheng Yi, Zhao Yingzi, and Han Dong. It premiered in Tencent Video on 10 September 2020 until 5 November 2020 every Thursdays-Saturdays. Beside that, it also aired at Line TV, LiTV, and iQIYI Taiwan.

This series tells about the ups and downs of the Great Sheng Kingdom from its turbulence to prosperity under the regency of Helan Mingyu, the Empress Dowager Xianzhen.

Princess Helan Mingyu (Zhao Yingzi) is a carefree, honest, bright but naive young lady who becomes acquainted with the 9th Prince Xiao Chengxu (Cheng Yi) by chance, in which the two get along well and eventually develop feelings for each other. Prince Xiao Chengxu, repeatedly, made military exploits to help his brother becomes the emperor and establish the Great Sheng Kingdom. However, fate turns against the couple, since his only real younger brother, Xiao Chengxuan's life depends on Princess Mingyu's hand. She is forced to marry Prince Xiao Chengrui (Han Dong) after news about Prince Chengxu's death spreads and she gets trapped in a cruel Harem life.

When the truth behind his mother's death is exposed, Prince Chengxu is determined to usurp the throne and take revenge, but Emperor Xiao Chengrui suddenly dies from an old illness of his after decreeing Prince Qiyuan, his son with Princess Mingyu, to succeed the throne, which keeps Prince Chengxu from usurping the throne. Prince Chengxu is forced to assist Prince Qiyuan until he reaches maturity while trying to revive his relationship with Princess Mingyu. As the time passed, Prince Qiyuan becomes dissatisfied with Prince Chengxu controlling him and hates him more after find out about his affair with his mother.

Princess Mingyu, the Empress Dowager, is now torn, as the desires and the needs of her people outweigh her own, forcing her to uses her wisdom to bring peace to her beloved people and the nation. However, Prince Chengxu, unexpectedly, dies in the battle while protecting Prince Qiyuan who passes away with his most favorite wife. For the sake of the Great Sheng kingdom's future, Grand Empress Dowager Mingyu, once again, must forget her needs and accompany her only living grandson to the throne.

Filming started in September 2018 and finished on 15 January 2019 at Hengdian World Studios.