The sponge city heat island effect monitoring was carried out by the remote sensing interpretation method. The heat island intensity was calculated by the Urban Heat Island Ratio Index (URI)，and compared to the same period of history or compared with the adjacent areas, the study region URI values decreased as a standard method system for sponge city heat island effect monitoring and evaluation. Taking Xianyang urban area as contract region, based on the results of ground temperature inversion from satellite images in the summer of 2015-2017, the heat island effect variation trend in sponge city construction of Fengxi New City was evaluated. The results showed that the heat island effect relieving of Fengxi New City was obvious in the three years of sponge city construction, and it proved that the sponge city construction eases the urban heat island effect.