Taking 304 family firms listed in Shanghai and Shenzhen as the samples, this paper firstly uses principal component analysis to extract the comprehensive performance factor, and then uses multiple regression analysis to study the relationship between the financing structure in family firms and the business performance. The research finds that the ratio of internal financing and the shareholding rate of actual controller, state-owned legal person and bank are positively correlated with the business performance, while asset-liability ratio and equity financing rate are negatively correlated with the business performance. The relationship between Z index, the shareholding rate of executives and the business performance depends on the different areas and industries. Finally, based on the research conclusions, this paper puts forward corresponding suggestions to optimize the financing structure in family firms and promote the enterprise operating efficiency.