Semiconductor power device and preparation method thereof

The invention provides a semiconductor power device and a preparation method thereof. The semiconductor power device comprises a drift layer located on one side of a semiconductor substrate layer; the gate structure is positioned on one side, deviating from the semiconductor substrate layer, of the partial drift layer; the well regions are respectively positioned in the drift layer at two sides of the gate structure and extend into the drift layer at the bottom of a part of the gate structure; a first source region located in the well region; the doped region is located in a partial region of the well region, the doped region sets the well region to comprise a first well and a second well, the doped region is located between the first well and the second well, and the doped region is connected with the drift layer outside the first source region and the well region; the conductive type of the doped region is opposite to that of the first well and that of the second well, and the conductive type of the doped r