In order to solve the problem of poor mechanical properties of aluminum alloy machining bright wheels and to meet high-end customer requirements such as Benz，BMW，Audi（BBA）. Firstly the effects of two kinds of improving coating process on the mechanical properties（yield strength，tensile strength，elongation，hardness）of machining bright wheels were discussed：low temperature curing power primer+ enamel +machining+KSL（Acute Angle protective paint）+ transparent powder，low temperature curing power primer+enamel+machining + transparent primer/high film thickness clearcoat（wet-on-wet）. Secondly the film properties of the sprayed hubs（e. g. film thickness，adhesion，chipping resistance，CASS，filiform corrosion，moisture and chemicals resistance）were investigated and evaluated. The results suggested that the improving coating process formed by low temperature curing power primer+enamel+machining+transparent primer/high film thickness clearcoat（wet-on-wet）with better mechanical properties than the existing coating process and qualified film properties could beapplied in small batches on the machining bright wheels of high-end customer.