The invention relates to a magnesium alloy chemical nickel plating solution. Every liter of the solution contains 30-35g of nickel sulfate, 25-30g of complexing agent sodium citrate, 30-35g of reducer sodium hypophosphite, 0.001-0.003g of stabilizer glycine, 30-35g of buffering agent sodium lactate, 0.005-0.01g of wetting agent nonylphenol polyoxyethylene ethe and the balance deionized water. The method comprises the following steps: polishing the surface of a magnesium alloy part, sanding, degreasing, dipping the magnesium alloy part into the chemical nickel plating solution of which the temperature is 80-90 DEG C and the pH value is 5-6, and applying a potential of -0.5 - -0.7V to carrying out anodic polarization for 30-120 seconds, wherein the magnesium alloy part to be plated is used as a working electrode, a corrosion resistant plate is used as an anticathode, and a saturated calomel electrode is used as a reference electrode; and after removing the external voltage, directly carrying out chemical plating in the nickel plating solution for 15-25 minutes, taking out the magnesium alloy part, washing with deionized water, rinsing and drying in the air. The invention is easy to operate, and has the advantages of low cost and less pollution; and the obtained chemical plating layer is uniform, and has the advantages of strong impact resistance, high corrosion resistance and good metallic appearance.