Abstract: In view of the high volume fraction of SiCp/Al composites processing problem,on-line electrolytic dressing(ELID) precision grinding processing technology is used to carry on precision grinding experimental study for SiCp/Al composites.First,by establishing single particle grinding model,the maximum grinding grain deformation of the chip thickness was obtained,and then using Matlab software,the scope of test parameters of the SiCp/Al composite plastic domain grinding was obtained.Second,through single factor experiment,the grinding depth,speed of grinding wheel and workpiece speed effects on machining surface roughness were obtained,and then compared the optimal parameters of the test obtained from orthogonal experiment with the scope of test parameters of the SiCp/Al composite plastic domain grinding obtained from theoretical analysis,the optimal process parameters were determined.Finally,carrying on precision machining for the volume fraction of 40%of SiCp/Al composites by using the optimal experimental parameters,the machined surface roughness of Ra 0.030μm was obtained.Research shows that applying ELID precision grinding processing technology and using W5 cast iron funds corundum grinding wheel,when the speed of the grinding wheel is 1 500 r/min,the grinding depth is 10 μm and workpiece speed is 2 m/min,the best grinding effect can be obtained.