As a basic component of society, the family's poverty vulnerability is not only affected by the risk impact brought by risk events, but also related to the family's own risk mitigation ability. The paper, based on the perspective of risk shocks and risk mitigation, selects data from the China Family Panel Studies (CFPS) to explore whether social capital can effectively reduce household poverty vulnerability. The results show that risk events increase household poverty vulnerability to some extent, while social capital can significantly reduce household poverty vulnerability and has a good risk mitigation effect; social capital can not only increase the probability of getting help from neighbors to obtain more social support, but also increase the per capita income level of families, thereby reducing the vulnerability of families to poverty. Meanwhile, the impact of social capital and risk shocks on poverty vulnerability has significant regional heterogeneity. In the western regions, social capital can more effectively reduce household poverty vulnerability and has better risk mitigation ability, but its impact caused by risk shocks is also higher than that in the eastern regions.