The purpose of this paper is to suggest practical suggestions to mitigate Urban Heat Island(UHI) problems in Daegu regarding urban surface temperature. Urban street trees's size and the relations between urban land use types and surface temperature are analysed using aerial photos, the numerical value map and Landsat TM image with special reference to Jung-gu. Total urban street tree's crown size is 156,217.6㎡ and it is equal to 2.24% of study area. In addition, the size of 'city and residential area' is 6,681,870㎡(95.7% of study area), which causes UHI and the total size of 'river' shows the lowest surface temperature area and 'road' and 'business and service area' are the highest surface temperature zones. Therefore, it is probable that the network between urban street trees and the lowest surface temperature areas mitigate UHI effects.