The research of spatial-temporal differentiation and mechanism of land-use/cover change (LUCC) is fundamental in landscape change science. In this research, the Haidian and Yanqing Districts of Beijing were taken as the study area, and the TM/ETM image of 1992 and 2002 were used as data source. The data were analyzed by transfer matrix and multiple linear regression to reveal the spatial-temporal changes and the mechanism of LUCC. Results indicated that: ① From1992 to 2002, urban built-up area in Haidian expanded much faster than that in Yanqing and the structure of urban land in Haidian changed intensively; Agricultural land in Yanqing decreased much less than that in Haidian and the structure of agricultural land in Yanqing changed obviously. Urban land in Haidian started to change into woodland, which was not detected in Yanqing. ② From 1992 to 2002, the main external driving forces of LUCC in Haidian were population growth, new technology blooming, real estate development and new urban planning policy of Beijing; The most important internal factor of Haidian was the former land-use. The main external driving forces of LUCC in Yanqing were the growth of nonagricultural population, the development of tourism, the adjustment of agricultural structure and the ecological development of Beijing. The most important internal factors of Yanqing is terrain. ③ LUCC was mainly policy driven in Haidian and economy development driven in Yanqing.