At present, the world's natural resources, ecological environment, and other security issues are becoming increasingly prominent; how to use natural resources to develop the economy and achieve the coordinated development of economic, social and ecological benefits is of great importance. Affected by the rapid population growth and extensive production and lifestyle, China also faces the dilemma of lack of resources and deterioration of the ecological environment. China has proposed a national sustainable development strategy to break through the predicament, including returning farmland to forests. Taking Qingyuan Manchu Autonomous County in China as an example, this paper used the multivariate linear regression analysis to explore the effects of five kinds of livelihood capital on non-agricultural income and the impact of farmers' livelihood capital on non-agricultural income with the regulatory implications of returning farmland to forests. The results show that: (1) Human capital, physical capital, financial capital, and social capital all have significant positive effects on nonfarm income, and natural capital, which has a significant negative effect on nonfarm income. Natural resources such as arable land and forest land are the natural capital that farmers depend on for survival, and the foundation must be protected.In terms of human capital, it is important not only to ensure the number of household laborers but also to improve the labor force's mastery of new technologies and skills. The increase in physical capital, such as basic means of production and infrastructure tools, the increase in funds at the disposal of the farm household, and the higher social capital, such as the presence of relatives who are cadres and the degree of interaction with relatives, all contribute to the transition from farm to non-farm and contribute significantly to the income of the farm household. (2) Results on the impact of livelihood capital on non-agricultural income based on the adjustment effect of returning farmland to forests: Except for the impact of social capital on non-agricultural income, the impact of the other four types of capital on non-agricultural income is significant, but the significance level is inconsistent, of which the impact of natural capital and human capital on non-agricultural income is significant at the 1%level, the impact of physical capital on non-agricultural income is significant at the 5% level, and the impact of financial capital on non-agricultural income is significant at the 10% level. The study puts forward suggestions such as increasing the subsidies for the policy of returning farmland to forest, and for the actual characteristics of the region, it is targeted to propose and develop the subsidy standards for returning farmland to forest. At the same time, increasing the subsidies for farmers, improving the ability of farmers to maintain and enhance social relations, increasing the credit support policies for farmers, and continuing to explore new ways to promote farmers' income.