Abstract: Southern Jiangxi, characterized by strong tectonic movements and much geothermal water, is one of the key areas for geothermal resources development and utilization in China. Taking the Zhashanli geothermal system in Shicheng County as an example, the paper discusses the characteristics and genesis of convective geothermal system in the fault-fold mountains of Southern Jiangxi, which is of practical significance to the search for geothermal resources and development and utilization of clean energy. The Zhashanli geothermal system takes the terrestrial heat flow provided by NNE fault as heat source, and forced convection as mechanism. Atmospheric rainfall penetrates through cracks and circulates in the deep fault zone, absorbing the heat of surrounding rocks and radioactive heat of deep magmatic rocks to form geothermal water, forming circulation under the effect of topographic elevation difference and water pressure difference, and forming hot springs along water flowing fissures in depressions.