The work aims to propose a synthetical surface quality assessment method and analyze the influence of process parameters on the surface quality of high volume fraction SiCp/Al, as well as optimize the grinding process in order to solve severe and complex surface defects of machined SiCp/Al. Surface defects of machined SiCp/Al were observed via SEM to present a synthetical assessment method based on primarily the overall surface roughness indicator SR which integrates multiple indicators and secondly surface topography. The full factor experiments were carried out to analyze influence of spindle speed and grinding depth on surface quality at low and high feed rate conditions separately. Abaqus simulation was conducted to reveal formation mechanism of grinded SiCp/Al surface and then explain the experimental results. During the experiment, at smaller grinding depths (ap were 5 mm and 20 mm), the overall surface roughness indicator SR progressively decreased first as the spindle speed ns increased) and then increased as ns increased; at larger grinding depths (ap were 40 mm and 80 mm), SR progressively or approximately decreased as ns increased from 2000 r/min to 8000 r/min. Conversely, at lower spindle speeds (ns were 2000 r/min and 4000 r/min), SR increased first and decreased second and then increased as ap increased from 5 mm to 80 mm; at higher spindle speeds (ns were 6000 r/min and 8000 r/min), SR increased first as ap increased and then decreased at low feed rate or increased at high feed rate as ap increased. The optimized grinding parameters for the best grinding surface quality included feed rate of 50 mm/min, grinding depth of 5 mm and spindle speed of 6000 r/min; and the one for both grinding efficiency and surface quality included feed rate of 50 mm/min, grinding depth of 80 mm and spindle speed of 8000 r/min. Therefore, the synthetical assessment method of machined SiCp/Al surface has high reliability, the influences of spindle speed and grinding depth on the surface quality present coupling nature. Decreasing grinding depth and adopt appropriate spindle speed can improve the surface quality.