Since China"s economic development has entered a new normal, the regional economic gap has changed from the East-West gap to the North-South gap. This paper first analyzes the main performance of China"s North-South economic gap from the total capital newly absorbed by enterprises and the registered capital of operating enterprises: It continues to widen and presents two-stage characteristics with 2013 as the boundary. Based on this, this paper uses the panel data of 285 prefecture-level cities in China from 2002 to 2019, and constructs an econometric model to analyze the influence of enterprise investment on economic growth of China, the north and the south from the perspective of supply side, and explores whether enterprise investment is an important factor to widen the economic gap between the north and the south of China. By building a panel threshold model, it further explores the influence of opening up and government intervention on enterprise investment on economic growth. The results show that: (1) Enterprise investment has a significant positive impact on the economic growth in both the north and the south, and its promotion effect on the economic growth in the south is much higher than that in the north. In addition, the investment amount obtained by enterprises in the south is much higher than that in the north, so the gap between the north and the south is further widened. (2) Taking 2013 as the boundary, the economic effects of enterprise investment in both the north and south regions will gradually weaken, but the promotion effect of enterprise investment on economic growth in the south is always higher than that in the north. (3) Whether in the northern or southern regions, the positive effect of enterprise investment on regional economic growth will be weakened with the improvement of opening up; (4) As far as the northern region is concerned, the positive effect of enterprise investment on regional economic growth increases with the decrease of government intervention, but there is no threshold effect for the southern region. On the whole, enterprise investment has widened the economic gap between China"s north and south to a certain extent, and the difference between the investment fields of enterprises in the south and north leads to the difference in the transformation of old and new kinetic energy, which may further widen the economic gap between China"s north and south.