This paper uses the conventional observation data collected from eight automatic weather stations in Lhasa in 2012-2016, and the related data of local industry, agriculture and residents’ living status, and assesses the spatiotemporal distribution of heat island effect in Lhasa and its relationship with landuse. The results show that the annual and seasonal changes of urban heat island in Lhasa are gradually increasing. The monthly variation of the urban heat island intensity is mainly concentrated in winter, followed by summer, and the heat island effects in spring and autumn are weak. The spatial distribution of the urban heat island is extremely uneven: high in the southwest and low in the northeast. Heat island area has expanded, and the center shifts southward from the economic development zone to the Liuwu Railway Station, with low value range located near the Tax Forest and the Lalu Wetland. The heat island intensity of Lhasa is positively correlated to population density, housing built area and reduced cultivated land area, and negatively correlated to afforestation area. It has no significant correlation with agricultural production.