On the basis of the analysis of the mechanism of the siphon effect after the opening of the high-speed rail, through the modified gravity model and the spatial measurement model, the space between the 11 prefecture-level cities in Jiangxi Province and the major cities in the neighboring provinces are calculated by using the “with or without comparison method”. The results shows that：The high -speed railway reduces the time and space of the city and strengthens the spatial interaction between Jiangxi and its neighboring provinces, especially Shanghai, Changsha and Wuhan；The high -speed railway makes the spatial distribution of the intensity of the siphon effect change significantly；The opening of high-speed rail will cause cities with strong economic power to produce a positive siphon effect to promote economic growth, while cities with poor economic development will have the opposite economic effect.