In order to adapt to the context of rural population contraction caused by urbanization, the local government has put forward a series of policies guiding rural space shrinkage development in southern Jiangsu. Based on the statistics data of rural population and the spatial vector data of rural land use in 2005 and 2017, this paper took Changshu city as the research area, then carried out a quantitative analysis of the trend of rural human settlement space change in different scales of county, town and village from four aspects, including rural population size, rural residential land use, internal structure and expansion direction. Finally, this paper identified different types and influencing factors of rural human settlement space change. Several conclusions were obtained as follows: (1) On the county scale, the rural human activity in Changshu was continually shrinking, but the rural human settlement space was expanding, especially in the south & southwest directions. Moreover, rural land use internal structure was becoming more non-agricultural, and overall state was diluted and extensive. (2) On the town & village scales, there were differences in change characteristics on different scales. Specifically, the rural human activity was in both contraction and expansion, and exhibited differently on different scales, which was more significant on the village scale. (3) The paper identified five types of changes in rural human settlements space of Changshu city, namely, urbanization oriented, industrialization oriented, transportation oriented, industrialization-transportation oriented and policy oriented, as well as explored its driving factors on a macro level. In short, the rural human settlement space change of Changshu city is driven by four factors containing urbanization, industry, transportation and policy. Also, this study could expand the multi-scale analysis method of rural Smart Decline, and even introduce a new theoretical perspective for the rural space transformation research.