Located between the Hall of Heavenly Purity and the Hall of Earthly Tranquility, the Hall of Union and Peace (Jiaotai Dian) implies that the union of the heaven and the earth bring peace forth. It was constructed in 1402 and rebuilt in 1789. The hall is similar with the Hall of Central Harmony  in its shape, but is comparatively small.

The empress held ceremonies here on the Spring Festival, the Winter Solstice and her birthday, receiving tributes from the imperial concubines, the princesses and the princes' wives. Since the reign of Emperor Qianlong (the fourth emperor of the Qing Dynasty), the hall was used to keep twenty-five imperial seals, each of which was designed for a certain purpose. These seals are laid in boxes which were covered with damask silk as what they were.

Behind a throne, visitors will see a screen with an article on it. This is an ode to the Hall of Union and Peace written by Emperor Qianlong. Above the screen, there are two characters on a plaque, which advise Emperors to govern the state by virtue. A clepsydra made in 1745 stands in the east of the hall. This device measures time by marking the escape of water, an ancient way used by the Chinese people. In the west, there is a chime clock which looks like a mini-pavilion. It was made early in 1789, but still can tinkle out the exact time today.

Next: Hall of Earthly Tranquility