Abstract: Based on remote sensing images of Taiyuan from 1973 to 2020, artificial visual interpretation and Google historical image correction are used to extract built-up areas. The compactness, expansion intensity, expansion speed and gravity center transfer model are introduced to analyze the spatiotemporal evolution characteristics of built-up areas in Taiyuan in the past 50 years. The main driving factors of expansion of Taiyuan built-up area are analyzed. The results show that:① From 1973 to 2020, the built-up area of Taiyuan has expanded by 15.12 times, with an average annual increase of 7.85 km²/a. The compactness of the built-up area is generally low and the expansion is obvious in the north-south direction. The center of gravity migrates more than 3500 m along the southwest direction of about 30°. ② The main factors causing the expansion of Taiyuan built-up areas are economy and population expansion, among which GNP and per capita GDP play a key role.

Key words: built-up areal, temporal and spatial changing, Landsat, expansion characteristics, driving force