Objective To study the effect of plating solution pH on the electroless plating process during the Co plating on the surface of TiCN powder. Methods Co was coated on the surface of TiCN powder by low-temperature electroless plating. The initial pH of the plating solution was adjusted by ammonium, and the effect of initial pH on the coating formation rate and the change of pH during the plating process were studied. Besides, the changes in phase composition and surface morphology of TiCN before and after plating were analyzed. Results Within the alkaline range, the plating rate first increased and then decreased with the increasing initial pH of the plating solution. The highest plating rate was observed when the initial pH of the plating solution was 9. During the plating process, the pH of the plating solution decreased obviously, with the production of a large amounts of bubbles. After 0. 5 h, the pH value became stable. A uniform Co coating formed on the surface of TiCN. Conclusion By adjustment the initial pH of the plating solution, the efficiency of Co plating on the surface of TiCN. High plating rate was observed at pH = 9 and 85 ℃ .