In order to improve the preparation efficiency and quality of magnetic abrasive prepared by electroless composite plating, the chemical reaction system for magnetic abrasive preparation was optimized.According to the optimized chemical reaction system, the preparation experiment of magnetic abrasive by electroless composite plating was carried out, and the properties of the prepared magnetic abrasive were tested.The results show that the concentration of succinic acid has a significant effect on the plating rate of the electroless plating reaction system, and the effect of citric acid concentration is less than that of succinic acid, the concentration of succinic acid and lactic acid has the least effect on the pH change of plating solution. The optimized electroless plating reaction system is citric acid concentration is 4 g/L, aminoacetic acid concentration is 9 g/L, succinic acid concentration is 19 g/L, lactic acid concentration is 26 g/L, nickel sulfate concentration is 32 g/L and pH of plating solution is within 5.0~5.4.Diamond content on the surface of the prepared magnetic abrasives is high and the diamonds are uniformly distributed. Service life of the prepared magnetic abrasive in ultrasonic assisted magnetic abrasive finishing of titanium alloys is more than 30 minutes