Energy consumption in cities and towns is related to the individual building and also the group morphology. In order to explore the impact of the spatial forms of small town residential blocks on energy consumption, by taking Changxing County of Zhejiang Province as an example, the morphological characteristics of small town residential blocks were analyzed according to the sample study of the residential blocks in central area, and five typical floor area ratios were extracted on the basis of spatial form types of typical residential blocks. Then, from the perspective of typo-morphology, based on the morphological characteristics of residential blocks in small towns, five “basic forms” and 17 “derived forms” were generated by the five typical floor area ratios. Finally, two-step energy simulation was carried out to analyze the influence of physical forms and immaterial forms on the energy consumption of residential blocks. Results show that the energy consumption intensity of multi-story slab building type was the lowest, and that of low-rise single building type was the highest. The mixed residential block was the most suitable residential block mode for small towns. Under the same floor area ratio, the energy consumption intensity of the block could be reduced by mixing the two types of residential buildings and placing the higher story residential buildings on the north side of the lower floor residential buildings. It is also more conducive to the energy saving of residential blocks by adopting the positive south and north determinant layout. In the process of planning and construction, it is necessary to adjust the factors of immaterial forms through the control of physical forms, thereby saving energy.