By using Landsat-5 TM images, the land surface temperature (LST), vegetation cover, and normalized difference moisture index (NDMI) in different areas of Guangzhou were extracted, and the effects of vegetation cover and NDMI on the land surface temperature of the City were studied, based on the landscape ecological methodologies. There existed good linear correlations among the vegetation cover, land surface temperature, and NDMI, but the correlation coefficients for any two of the three items differed obviously with different areas. If the vegetation cover in different areas of Guangzhou was improved to the same level, urban center had the best cooling effect, followed by the suburbs in the north edge of urban center. The forest parks in different areas of the City also had different cooling effect on the surrounding environment. The difference of the average temperature between the 960-1080 m buffer zone and the inner park were 4.69 degrees C in Baiyun Mountain, 1.27 degrees C in Mazaishan, and 0.41 degrees C in Liuxihe. High vegetation cover could increase the thermal landscape heterogeneity and the aggregation among different landscapes, and promote the energy exchange between the lower temperature patches and higher temperature patches, playing an important role in controlling hot island effect. NDMI and vegetation cover had the same effects on the formation of thermal landscape pattern.