Due to NJFET’s poor consistency of saturated current in fabrication, experimental studies were conducted on saturation current process influencing factors from first oxidation, gate implantation and gate annealing process, and process optimization and control methods were proposed, resulting in effective control of device saturation current parameters. The stability is improved from 6.9% to 0.38% and the yield is increased from 85% up to 96%, which significantly improve the product quality and reduced the cost.