The Gate of Supreme Harmony Square was the entrance of the Outer Court during the Ming and Qing dynasties. The Gate of Supreme Harmony is the main front gate of the Outer Ccourt, where the emperor met with its courtiers during the Ming dynasty and the early Qing dynasty (Emperor Kangxi changed the venue to the Gate of Heavenly Purity). Unlike what is plotted in many TV dramas, the emperor did not give audience to his courtiers inside the Hall of Supreme Harmony, but rather issued edicts and addressed state affairs here. Only grand assemblies, celebrations and sacrificial ceremonies were held inside the Hall of Supreme Harmony.

Sitting on a white marble platform, the Gate of Supreme Harmony is 9 bays wide and 4 basy deep, circled by white marble banisters and covered by a double-eave, gable-and-hip roof.