This paper presents a study on surface roughness generated by high speed milling of high volume fraction (65%) silicon carbide particle-reinforced aluminum matrix (SiCp/Al) composites. Typical 2D (Ra and Rz) and 3D (Sa and Sq) surface roughness parameters were selected to evaluate the influence of the milling parameters on the surface quality in comparison with aluminum alloy. The 3D topography of the milled surface was studied as well. The results indicate that 3D parameters (Sa and Sq) are more capable to describe the influence of the milling parameters on the surface quality, and among them Sq is preferable due to its good sensitivity. Sq decreases with milling speed and increases with feed rate. The influence of axial depth of cut (ADOC) is negligible.