To break through the technical bottleneck of low bonding strength of thermal protective coatings prepared by plasma spraying on aluminum alloy surfaces, a three-cathode plasma spraying system was used to prepare 8YSZ thermal protective coatings on the surface of 7A04-T6 ultra high strength aluminum alloy. With the help of scanning electron microscope, X-ray diffractometer, microhardness tester and universal testing machine, the effects of different gas flow parameters on the micromorphology, phase composition, microhardness and bonding strength of the coatings were analyzed and characterized. Finally, the critical value of the influence of gas flow parameters on the bonding strength of the coating was proposed. The results showed that the upper surface of the coatings prepared under different gas flow parameters all had molten and semi- molten powder particle morphology, pore structure and crack propagation morphology. With the increase of gas flow, the density of the coating increased, and the tamped morphology of the coating showed a trend of increasing first and then decreasing. The phase structure of the coating prepared under different gas flow parameters was basically consistent with the feed powder, and there was only a single component of Zr0.92Y0.08O1.96. With the increase of gas flow parameters, the average microhardness of the coating showed a gradually increasing trend. With the increase of gas flow parameters, the average bonding strength of the coating showed a trend of increasing first and then decreasing.