As the largest one of the five capitals in Liao Kingdom, the Middle Capital is made up of outer city, inner city and the imperial city with a wall as long as 15 kilometers. The outer city extends 4.2 kilometer from north to south and stretches for 3.5 kilometers from east to west. The remains of the wall still stand 4 to 6 meters high. According to archaeological discovery, an area to the south of the city used to be a Hans residence area, where there were architectures like market, temple, civilian residences, post house and government office. The Relic of Middle Capital in Liao Kingdom possesses huge archaeological value in the study of ancient Qidan’s survival and development.