A semiconductor element and a manufacturing method thereof are provided. The semiconductor element includes a base, an epitaxy layer, a first well, a second well, a third well, a first heavily doping region, a second heavily doping region, a implanting region and a conductive layer. The epitaxy layer is disposed on the base. The first well, the second well and the third well are disposed in the epitaxy layer. The third well is located between the first well and the second well. A surface channel is formed between the first heavily doping region and the second heavily doping region. The implanting region is fully disposed between the surface channel and the base and disposed at a projection region of the first well, the second well and the third well.