Urban heat island (UHI) effect is one of the most important issues in urban ecology. Based on FY-3C/VIRR LST data, the temporal and spatial variation characteristics of urban heat island effect in Shanghai in 2019 were quantitatively analyzed by calculating heat island intensity index and heat island proportion index in the study area. The results show that : the total heat island area of Shanghai in 2019 is more than 40%, and the urban heat island effect is significant, and the total heat island area of Shanghai in July is the largest; the spatial distribution of the heat island effect in Shanghai presents a pattern of "hot in north and cold in south", and the heat island effect is mainly distributed in the central and northern part of Shanghai; the tropical proportion index of Shanghai was relatively high from May to July, and it was a serious heat island. With the continuous increase of average surface temperature in August, the heat island proportion index decreased.