The geo-economic relationship between China and South Asia is of great significance to its trade development. Using the trade gravity model, the trade data between China and five countries from 2000 to 2022 was selected to analyzes the trade effects of their geo-economic ties. The regression results show that the geo-economic ties between China and South Asian countries have a restraining effect on China's trade with South Asian countries, while the GDP, geographical distance, electric infrastructure, political stability, government efficiency and rule of law environment have a promoting effect on China's trade with South Asian countries. Therefore, in the future, on the basis of the "Belt and Road" initiative, China should adjust the structure of import and export commodities to South Asian countries, optimize infrastructure construction, promote economic development, improve national income level, provide policy support, strengthen geo-economic cooperation and trade with South Asian countries, and deepen trade cooperation between China and South Asian countries. It is of great significance to promote regional linkages and development.