A silicon on insulator integrated high-current N type combined semiconductor device, which can improve the current density, comprises a P type substrate and a buried oxide layer arranged thereon. A P type epitaxial layer divided into a region I and a region II is arranged on the buried oxide layer. The region I comprises an N type drift region, a P type deep well, an N type buffer well, a P type drain region, an N type source region and a P type body contact region; a field oxide layer and agate oxide layer are arranged on a silicon surface, and a polysilicon lattice is arranged on the gate oxide layer. The region II comprises an N type triode drift region, a P type deep well, an N type triode buffer well, a P type emitting region, an N type base region, an N type source region and a P type body contact region; a field oxide layer and a gate oxide layer are arranged on a silicon surface, and a polysilicon lattice is arranged on the gate oxide layer. It is characterized in that the N type base region is wrapped in the N type buffer region, and the drain electrode metal on the P type drain region is connected with the base electrode metal on the N type base region by a metal layer. In this invention, the current density of the device has been obviously improved without increasing the device area and reducing other performances of the device.