In order to explore the spatiotemporal evolution of land use/vegetation cover in the process of urbanization in mountainous new development area, taken Yubei district of Chongqing as the research area, the historical images of Yubei district from 1995 to 2020 were interpreted by remote sensing, based on the land use transfer matrix, the spatial and temporal evolution characteristics of LUCC in the 6 period of Yubei District were analyzed. The spatial and temporal evolution of normalized vegetation index (NDVI) was analyzed by using binary pixel model to calculate vegetation coverage, and the impact of LUCC change on vegetation coverage was quantitatively evaluated. The results show that from 1995 to 2020, the urban construction land in Yubei District was mainly occupied by farmland. The center of gravity of the city moves to the southwest slightly, the construction land deviated from compact, and the shape expanded to complicate development. The NDVI of yubei District decreased by 1%/a from 1995 to 2020, and the NDVI of all land types decreased. The overall spatial trend increased first and then decreased, and decreased significantly in the southwest and central eastern regions after 2010. The fluctuation of NDVI was the largest in summer and the smallest in winter. The vegetation coverage was mainly affected by temperature in summer and precipitation in autumn. NDVI in four seasons showed an increasing trend from central to south and north regions, which was similar to urban spatial expansion. The contribution rate of climate fluctuation to the total change of vegetation cover in Yubei district was 14.22%, and temperature was the main factor affecting NDVI. The contribution rate of land use change to vegetation cover change in the study area was 85.78%, and its influence gradually increased. Farmland contributed the most to vegetation cover change in each period, the expansion of construction land's contribution to the vegetation coverage rate increased.