To clear the influence rule that the spatial pattern process of thermal comfort degree affected by urban heat island, and to provide theoretical support to the reasonable layout of city space, this paper constructed the criteria for the classification of thermal comfort degree affected by surface heat island effect, adopted the same phase of TM remote sensing data and ground measured data at the same time based on human comfort and human physiological reaction for the environment temperature. Utilizing the landscape pattern index evaluation method, this paper analyzed the urban heat island effect in downtown Tianjin from 1992 to 2011. The results show that, first, the space area is expanding of the thermal comfort degree affected, and the impact intensity is rising; second, for the secondary thermal comfort degree affected regions, the largest patch area is decreasing, but the total area is increasing; third, for the third and fourth thermal comfort degree affected regions which cause people feel discomfortable, patch classes area, the largest patch area, patch density are rising, indicating the heat island effect on the thermal comfort in the continuing deterioration; fourth, the fragmentation of heat island landscape patch, the mixture of patch types, the reduction of connectivity among strong heat island areas can weaken the impact of the urban heat island effect on thermal comfort; fifth, although saving land, high-rise residential building will increase the total area of deteriorating thermal comfort and make the local thermal comfort affected by super grade.