The geo-economy of South Asian countries is of great significance to China's promotion of the Belt and Road Initiative. Using the modified gravity model, the geo-economic correlation between China and 6 countries in South Asia was measured, and the temporal evolution and spatial pattern change were analyzed. The results show that the geo-economic correlation between China and South Asian countries shows a trend of rapid growth during 1992-2021, but the growth trend is different from that of different countries. The spatial distribution pattern of geo-economic correlation between China and South Asian countries has little change, showing the characteristics of overall stability and local changes. The geo-economic correlation between China and the six countries in South Asia can be divided into five types: high correlation type, medium high correlation type, medium correlation type, low medium correlation type and low correlation type. Therefore, in the future, China should deepen economic and trade cooperation with South Asian countries on the basis of the "One Belt and One Road" policy support, and actively promote economic and trade exchanges with South Asian countries, which has certain positive significance for deepening the geo-economic cooperation between China and South Asian countries and promoting bilateral connectivity.