The understanding of urban design indices determining the temperature is essential to achieve climate adaptive design. However, the thermal effect of design indices has not been clarified due to its dependency on urban morphological features. In this study, the local climate zone (LCZ) scheme was employed to clarify the correlation between urban forms and the thermal environment. Taking the case of Shanghai, China, decisive design indices of the thermal environment were investigated for LCZs with different morphological features by remote sensing and numerical simulation. Results indicated that the thermal effects of the design indices depended on the morphological features of LCZs. The building footprint ratio showed positive effects on the surface temperature, but negative effects on the air temperature of low-rise and high-rise LCZs. Increasing the building height decreased the temperature of mid-rise and high-rise LCZs, but improved the temperature of low-rise LCZs. Indices of vegetation and surface materials presented stronger effects on the temperature of mid-rise, low-rise, and low-density LCZs. To improve the urban thermal environment, design strategies should be selected according to the morphological features to achieve efficient cooling effects.