Utilizing land cover change (LCC) information together with MODIS land surface temperature in Jing-Jin-Ji area in 2000, 2005 and 2010, spatiotemporal difference of urban heat island (UHI) effects and the factors influenced UHI is explored. Results reveal that the seasonal fluctuations of daytime UHI is bigger than that of nighttime UHI. More than 92.8% of the urban have UHI in the nighttime every season. The strongest daytime UHI happens in summer, but more than 85% of the cities have urban cooling effect in winter. The nighttime UHI in different seasons appear to be similar. The water in urban has different influence to UHI in daytime and nighttime which is to weaken the UHI and to enhance the UHI. The grass in urban enhance the UHI in the daytime of spring and summer and in the nighttime of all seasons but weaken the UHI in the daytime of winter. The forest and the crop land in the urban have the same effect which are weaken the UHI in the daytime of spring, summer and autumn and in the nighttime of all seasons but enhance the UHI in the daytime of winter.