A new process for improving the performance of n-LDMOS devices is proposed based on XXX's 0.18μm standard process flow. Adding an ion implantation at the common source of NLDMOS can extract the substrate charge and optimize the breakdown voltage (BV) and specific on-resistance (R_sp) of the NLDMOS devices. In this paper, by selecting different implant ion concentrations and rapid thermal annealing time, changes of BV and R_sp of the devices are studied. Because the ion activation efficiency is insufficient, simply increasing the implant ion concentration by 20%, the withstand voltage performance of the device has less improvement. By combining 20% increase in implant ion concentration with 20s rapid thermal annealing method, the BV of the NLDMOS device is increased by about 2.7%, while the R_sp is increased by only about 0.9%.