Due to the high breakdown voltage characteristics of the laterally diffused metal oxide semiconductor (LDMOS), this device is a protection device that prevents electrostatic discharge (ESD) in high-voltage applications. In the traditional structure, the robustness of LDMOS is relatively poor, which is caused by the inherent uneven conduction characteristics of the device itself and the Kirk effect. The silicon-controlled rectifier (SCR) can be embedded in the LDMOS structure to become the NPN_LDMOS structure. However, the inherent positive feedback effect of the SCR will cause its holding voltage to be lower and increase the risk of latch-up. A new type of device based on NPN_LDMOS was proposed, which could achieve a higher holding voltage and a small area. Based on TCAD simulation, the simulation TLP experimental results showed that the holding voltage of the device was increased from 7.3 V to 22.5 V, and the chip area was not increased, which proved that this structure had excellent immune latch-up capabilities.