As a colonial style urban space, the shophouse became one of the most important urban spatial types in the south of china, such as Canton city. The article attempts to re-introduce the mechanism, through researching the contribution of scale on the microclimate of shophouse streets via simulation software (ENVI-Met). Two groups of experiments were conducted by varying only the width of road and verandah, according to a certain scale range. After comparing the PET of monitoring points in different streets, conclusions on range of scale can be obtained, which will contribute to better microclimate in the shophouse street.