Based on the action mechanism of electroless nickel deposition, the factors affecting the stability of the plating solution, such as salinity ( nickelous sulfate and sodium hypophosphite ) , pH value, temperature and operating methods were analyzed. It is indicated that when the concentration of Nickel and hypophosphite acid is 5 . 8 g / L and 17 . 4 g / L respectively, and pH value is 4 . 4 , the best plating stability can be achieved under 82 ℃ .