Urban heat island (UHI) effect is very important to city development planning, city environment protect and ecological construction. The MODDIS data including land surface temperature and NDVI is used to analyze the distribution and structure features of UHI in Chengdu city. And the impact of NDVI on the land surface temperature is interviewed. Then the trend of UHI effect is researched. The results show that there exits remarkably negative spatial and temporal correlation between heat island intensity and NDVI. The NDVI in central city in Chengdu is poorest in central city and the land surface temperature is accordingly highest. The vegetation of western and southern city is relatively well, and the land surface temperature is relatively lower, where the UHI effect is weaker than that of other regions. The UHI effect has clear seasonal difference. It is stronger in summer than in winter. From 2002 to 2008, the UHI effect is enhancing slowly. The annual temperature difference between the city and urban increased about 0.5°C.