Based on the relevant data of A-share listed companies in Shanghai and Shenzhen from 2009 to 2019, internal integration indicators was used as mediating variables to empirically study the impact of core enterprise participation in supply chain finance activities on corporate financial performance. The results show that the participation of core enterprises in supply chain finance activities can reduce period costs and improve the financial performance of enterprises through internal integration. Further research shows that this effect is more significant for non-state-owned enterprises. Therefore, core enterprises should take a more proactive approach in participating in supply chain finance activities to achieve overall cost reduction and efficiency within the supply chain, as well as strengthen cooperation within the industrial chain.