The work aims to improve the bonding strength and surface and section hardness of the Al2O3-3%TiO2 composite coating on aluminum alloy matrix by plasma spraying through the optimization of plasma spraying process parameters. Four key spraying parameters affecting the bonding strength and surface hardness of spray coating were optimized by orthogonal test, thus the optimal parameters of adhesive bottom coating Ni-5Al and working surface Al2O3-3%TiO2 were obtained respectively. The order of factors influencing the adhesive bottom coating quality was current, distance, H2 and Ar flow, and the preferable level was 2, 3, 2 and 1. The main sequence of factors influencing the comprehensive index of working surface coating was spray distance, H2 flow, current and Ar flow, and the optimal horizontal number was 2, 3, 2 and 1. The best spraying parameters of the adhesive layer Ni-5Al were: spraying distance of 120 mm, spraying current of 520 A, Ar flow of 42 L/min and H2 flow of 7.5 L/min. The optimal spraying parameters of Al2O3-3%TiO2 composite coating were: 90 mm spray distance, 530 A spray current, 46 L/min Ar flow and 7.8 L/min H2 flow. The bonding strength of the bottom layer reached 25.2 MPa and 17.8 MPa at the surface coating. The mean hardness of the optimized working surface coating was above 1000HV0.5. High quality and stable Al2O3-3%TiO2 composite coating can be obtained by optimizing the spraying process parameters. Compared with coating prepared by the non-optimal spraying process parameters, each index of the coating quality is greatly improved.