Bonding zone behavior of aluminum matrix composite SiCw/6061Al, containing that of matrix-matrix, matrix-enforcement, enforcement-enforcement, was studied in this paper. It is found that there is a 'critical temperature' in the temperature liquid/solid two-phase regime of aluminum matrix composites. When the welding temperature reaches this critical temperature, a certain amount of liquid matrix metal appears in the bonding area, which not only leads to the perfect bonding of the matrix-matrix (M/M) and reinforcement-matrix (R/M) interface, but also changes the reinforcement-reinforcement (R/R) interface to a reinforcement-matrix-reinforcement (R-M-R) interface. Processing at this temperature leads to a high-strength joint. At the same time, by controlling welding pressure between the solidus and liquidus temperature of aluminum matrix composites, the net shape joint of aluminum matrix composites is attained. The deformation of welding joint is controlled to less than 1%, so the net shape bonding of aluminum matrix composites is achieved.