A two-stage protection SCR (TSPSCR) was proposed to reduce the trigger voltage. The P-ESD layer was implanted in the traditional LVTSCR, and an additional diode was added. Because of the higher doping concentration of P-ESD layer, the device could trigger the first-stage discharge path by avalanche breakdown earlier, thus opening the second-stage discharge path. The Sentaurus TCAD simulation results showed that compared with conventional SCRs, the device had a lower trigger voltage from 10.59 V to 4.12 V, a maintenance voltage of 1.25 V, and a leakage current of 7.85 nA at 1 V DC voltage. The optimized TSPSCR could be used in advanced circuits with 1 V operating voltage.