The invention discloses an LDMOS device. The LDMOS device includes a drift region, a body region, a gate structure, a source region, and a drain region, wherein the gate structure is formed by overlaying of a gate medium layer and a polysilicon gate; a cavity injection region formed by a P+ region is formed in the drift region at the outer side of the drain region; the depth of the cavity injection region is greater than the depth of the drain region; a charge storage region formed an N type doped region is formed in an accumulation region; when the device becomes conductive, the cavity injection region provides cavity injection to reduce the conduction resistance, and the charge storage region is used to block cavity drift; and the doped concentration of the charge storage region is greater than the doped concentration of the drift region, and the doped concentration of the charge storage region is less than the doped concentration of the body region, so as to enable exhaust of the drift region to be decided by the doped concentration of the body region and the drift region when the device is cut-off. The LDMOS device can reduce the conduction resistance of the device, and can maintain good breakdown voltage at the same time.