Financial integration is an important support for the“Belt And Road”initiative, and meanwhile, it is the key determinant of firm’s internationalization. The uncertainty in the financial external environment of most countries along the“One Belt And One Road”may lead to the dilemma of the survival capability of Chinese OFDI firms. Based on the perspective of “institution-based view - resource-based view”,this research innovatively constructs an assessment system of financial ecological environment ,deeply analyzes the mechanism of the impact of the host country’s financial ecological environment on the operating performance of Chinese OFDI firm’s from the micro level, and focuses on the moderating effect of financial ecological environment on firm’s internal financing constraints. Taking the OFDI decision through 30 countries along“Belt And Road”,conducted by 204 Chinese listed firms from 2013 to 2017, the empirical results reveal that the good financial ecological environment of the host country is conducive to improving the viability of the sample firms and easing their internal financing constraints, and especially private firms and green field investments. The characteristics of“risk appetite”of state-owned firms and cross-border M&A have been proved.