Automobile 6061 aluminum alloy materials has been taken as the research object,the samples have been obtained by the metallurgical technology by adding reinforcing phase fly ash,the cutting theory model under different process parameters have been established based on the grey multi response optimization theory,at the same time the cutting experiments under different process parameters have been conducted,the effects of different process parameters on the cutting of the automobile 6061 aluminum alloy materials have been studied by the theory and experimental methods. The research shows that with the increase of strengthening phase fly ash,the automobile 6061 aluminum alloy material hardness increases,its density showed a trend of opposite; with the increase of cutting speed,fillers,the surface roughness of composite automotive materials gradually reduce,the surface roughness increases with the increased of the feed; PCD cutting tool machining of complex automotive materials surface roughness significantly below K10 hard alloy cutting tools; the relative error value of theoretical calculation value and experimental is small to verify the correctness of the theory and test methods,and the engineering feasibility for improving the application of the new automotive aluminum alloy composite material preparation and cutting technology.