The Regional Comprehensive Economic Partnership (RCEP) is the world's most populous free trade area with the largest economic and trade scale and the most development potential, and it will officially come into force in 2022, providing an opportunity for RCEP member countries to attract investment from China. Based on the information of economic and demographic characteristics of RCEP member countries from 2012 to 2020 and the panel data from China's ODFI, this paper measures and examines the influencing factors of China's direct investment in RCEP member countries by constructing a bidirectional fixed effects panel model of China's direct investment in RCEP countries. It is found that: the host country's net per capita national income, per capita GDP growth rate, merchandise trade and service trade inhibit China's investment in RCEP member countries, while the host country's GDP growth rate, per capita GDP can promote China's investment in RCEP countries, the host country's industry, exchange rate, and legal indices are not the main factors affecting China's direct investment in RCEP, and should be used in the comprehensive investment decision-making when On the basis of considering the unbalanced economic development of each country, the optimal layout of China's direct investment in RCEP member countries should be co-ordinated to provide more opportunities for Chinese enterprises to enter the markets of RCEP member countries.