The influence of complexing agent, solution pH value and temperature on the quality of electroless nickel plating of diamond powder at low temperature were investigated. At the temperature of 35 ℃ and the pH value of 5, the stability of plating solution, deposition rate, morphology and phosphorus (P) content of electroless nickel plating coating were tested and analyzed by changing the ratio of complexing agent. The results show that C6H8O7·H2O (20 g/L)+(CH2)2(COOH)2(5 g/L) is the best complexing agent in test samples. The electroless plating solution corresponding to the complexing agent has good stability and rapid deposition rate (0.391 5 g/h), and the obtained coating is leak-free and dense, with P weight content of 11.73%. The deposition rate, morphology and P content of electroless plating samples were measured and analyzed by changing pH value and temperature of plating solution with the best complexing agent. The results show that when the temperature of the plating bath is 35 ℃ and the pH value is 3~13, the deposition rate increases and the P content gradually decrease with the increase of the pH value. When the pH value is higher than 11, the rapid reaction rate is difficult to stabilize the pH value of the plating solution, and the plating solution is easy to decompose, so the pH value is more suitable within 5～11. The effect of temperature on plating was studied in the range of 30~50 ℃ at solution pH value of 5. It is found that the deposition rate and P content increase with the increase of temperature, and the plating layer is dense and leak-free. When the temperature is higher than 45 ℃, the reaction rate is too fast and it is not easy to stabilize the pH value of the plating solution, so the temperature is more appropriate in the range from 35 ℃ to 45 ℃.