Chinese ancient city wall is an important historical cultural heritage and the city scale is one of the important contents of ancient city form. Through the comprehensive and quantitative analysis of the perimeters reflecting the scale of city construction in the Ming Dynasty, the paper explores the distribution law of city in the Ming Dynasty. It is found that the scale of city in Ming Dynasty shows obvious hierarchy features and geographical features. The factors influencing the scale of a city include both man-made factors including hierarchy, history, politics, economy, and population, and objective factors including location and geographical environment. However, in many factors, the hierarchy of a city is still the most important factor that dominates the scale of a city in the Ming Dynasty