To analyze the influence of the changes in city underlying surface on human comfort, air temperature, relative humidity and wind velocity are observed in Nanjing University of Information Science and Technology with different kinds of underlying surface as woods, lawn, and bare land in April and May 2006. The data of air temperature, relative humidity, and wind velocity are used to evaluate the influences of climate environment on human comfort. Based on fuzzy mathematics, the comprehensive evaluation of human comfort for different kinds of underlying surfaces is made. The results show that from April to May it is the most comfortable on the lawn,while the least comfortable in the woods, and the that of woods is lower than that of lawn and bare land.