In order to evaluate the urban thermal environment of Chengdu city from 1988 to 2013, the land surface temperature and remote sensing images are taken as indexes and data sources. The results show that the high temperature region of urban thermal field migrates outward, and it is transferred to the area between the third ring and circular highway in 2013. The extra-high temperature area decreases year by year, and it is reduced by 1.83 km2 annualy from 2005 to 2013, the areas of high temperature and sub-high temperature increase by 26.90 km2 and 45.35 km2, respectively. The change rule of urban heat island intensity (UHII) is first decrease and then increase and finally decrease in four periods, and the strongest of UHII is 4.37 ℃ in 2005. The UHII is weakened in 1988 and strengthened in 2013 from area of the first ring to circular highway, the maximum values are 5 ℃ and 2.93 ℃ respectively in the two years. The change rules of land surface temperature and vegetation coverage values are fluctuant along the west to east direction with negative correlation, and the certainty factor is 0.5744.