A method for manufacturing a semiconductor device is disclosed. The method includes: forming a LDMOS region, an offset drain MOS region, and a CMOS region; simultaneously forming a first well in the LDMOS region and the offset drain MOS region; simultaneously forming a second well in the first well of the LDMOS region and the CMOS region; and forming a second well in the CMOS region, wherein a depth of the first well is larger than a depth of the second well and the second well is a retrograde well formed by a high energy ion implantation method.