Introduction to the city wall: The section of the city wall is trapezoidal, with a foundation trench dug below and slope protection on both sides. It is all built with soil rammed in sections. There are dense ramming and pestle marks with circular pointed bases or rounded bases on each level, and the city walls also have traces of block building. The circumference is nearly 7 kilometers, of which the north wall is about 1,690 meters long, the west wall is about 1,870 meters long, and the south and east walls are both about 1,700 meters long. The wall base is 20-32 meters wide, and the highest remaining ground level is about 5 meters.