The farmers’ livelihood capital is an important dependence of their resisting serious illness risk. This article first expands the sustainable livelihood theory by integrating the dimensions of psychological capital,and then uses the survey data from the three provinces of Guangxi,Hubei,and Jiangxi to quantify the livelihood capital of rural households. On this basis,the Heckman two-stage model is used to explore the impact of farmers’ livelihood capital on the risk of serious illness from the dual perspectives of the structure and level of livelihood capital. The study found:①The livelihood capital of rural households has an imbalanced structure and level. The order of the measured values of various capitals is psychological capital>social capital>human capital>financial capital>physical capital>natural capital. Psychological capital is the most abundant natural capital is the most deficient. Structurally,53.46% of the households belong to the weak capital type,and 39.63% and 32.52% of the total sample respectively belong to psychological capital dominant and social capital dominant households.②The sub-dimension level of farmers’ livelihood capital has a significant impact on whether rural households suffer from serious illnesses. Among them,physical capital,financial capital,and social capital have a significant negative impact on whether rural households suffer from serious illnesses.③For farmers affected by serious illnesses,both the structure and level of the farmers’ livelihood capital play a significant role in reducing the severity of the risk of serious illness. At the level,the total amount of capital and the level of the sub-dimension both have a significant negative impact on the severity of the risk of serious illness; structurally,the ability of human capital dominate and financial capital dominate households to resist risks is stronger.