With the further deepening of the international division of labor and the further extension of the global value chain, the diversification of export products from countries around the world has been further enhanced. "The impact of the initiative on the diversification of China's export products has important practical significance. Firstly, this paper introduces the Herfindal-Hirschman index (HHI) to measure the diversification of export products, and analyzes the current situation of the diversification of export products from countries along the Belt and Road to China based on the data from 2010 to 2019; Secondly, this paper matched CEPII data, United Nations data, World Bank WDI data and the data of the "Belt and Road" cooperation agreement signed with China to form the sample data of 63 countries from 2009 to 2019. Based on the pseudo-natural experiment framework, the dual difference model is used to test the relationship between the participation of countries along the Belt and Road Initiative and the diversification of their exports to China. The research perspective is focused on participating countries and non-participating countries, and a comparative analysis is conducted to explore whether joining the Belt and Road Initiative is conducive to improving the diversification level of export products from countries along the Belt and Road initiative to China compared with countries not participating in the Belt and Road Initiative; Finally, based on the qualitative analysis and empirical analysis above, this paper puts forward a series of countermeasures and suggestions, such as focusing on exporting domestic competitive products, reforming the exchange rate management system and promoting the development of cross-border e-commerce.