Abstract: Due to the local inhomogeneity of the internal structure of metal matrix composites represented by SiCp/Al, the traditional two-dimensional roughness parameter index is limited to describe and study the surface topography of the specimens of such materials, while the three-dimensional roughness parameter can reflect the surface characteristics of the specimens in a more comprehensive and detailed way. In this paper, $ 3\mathrm{D} $ parameters were used to characterize the surface of SiCp/Al specimens. Orthogonal tests were used to make the relationship between grinding process parameters and $ 3\mathrm{D} $ parameters (Sa, Sq, Ssk, Sku, Sbi, Sci, Svi) transparent and data-based, such as the influence weights of grinding parameters on $ 3\mathrm{D} $ indexes and the comprehensive indexes of multiple $ 3\mathrm{D} $ parameters. The surface morphology of the specimen is complex, including grooves caused by grinding wheel abrasive particles scratching on the soft aluminum matrix, pits caused by SiC particles being pulled out, and scratches caused by falling or broken SiC particles dragging with the grinding wheel. Due to the melting of aluminum matrix caused by grinding heat, there is the phenomenon of aluminum matrix smearing. Surface topography is significantly affected by grinding parameter changes, and it is found that different grinding parameters have different weights on the $ 3\mathrm{D} $ surface topography index, revealing that the number of grinding wheels has the most prominent influence on Sa index. With the increase of the grinding wheel mesh, the weight decreases from 34% to 13%, and the spindle speed, feed speed and grinding depth begin to become significant influencing factors, all gradually increasing from the initial weight of 22% to 29%. The optimal grinding parameter combination corresponding to the comprehensive evaluation index of 3D parameters is A_m 320#, V_s is 4 000 r/min, V_f is 20 mm/min, and a_p is 20 μm.