Abstract: In this paper,10 urban stations and 15 suburban stationswere selected by Fuzzy C-means Algorithm and Elimination Method to calculate the urban heat island Intensity (I _UHI).The hourly air temperature of 25 automatic meteorological stations is used to study the variation characteristics of the urban heat island effect in 2018.The results show that there is urban heat island effect in Mianyang in 2018,the average I _UHI is 0.64℃,characterized by weak level of the urban heat island;The urban heat island effect was strongest in winter,followed by spring,summer was as same as autumn;the highest I _UHI was in March,while the lowest I _UHI was in July.The urban heat island effect in Mianyang had obvious day-time variation characteristics.The intensity at night was obviously higher than that at daytime,and the maximum I _UHIoccurs almost at night.