Effects of diffusion welding process parameters on strength of welded joint based on particle reinforced aluminium matrix composite Al 2O 3p /6061Al have been studied through comparing with aluminium matrix alloy. The mechanism for loss of joint strength has been analyzed. It should be pointed out that key processing parameters affecting the strength of joint was welding temperature. The high quality joint can be successfully obtained with appropriate diffusion welding parameters. Effects of diffusion welding process parameters on strength of welded joint based on particle-reinforced aluminum matrix composite Al 2O 3p / 6061Al have been studied through comparing with aluminum matrix alloy. The mechanism for loss of joint strength has been analyzed. It should be pointed pointed that that key processing parameters affecting the strength of joint was welding temperature. The high quality joint can be successfully obtained with appropriate diffusion welding parameters.