The surface micro-structure of an explosive part affects its performance, measured precision of the part, and reliability of the weapon parts. The 3D surface micro-structure of the pressed PBX lathed surfaces was detected. The 3D and 2D surface roughness parameters were evaluated and analyzed. The results show that 3D surface roughness parameter is suitable for evaluating PBX machined surface with random distribution caving and pits defects. The 3D surface roughness parameter evaluation is better than that of 2D surface roughness parameter. Under the same evaluating parameters, PBX 3D surface roughness using round tool is much less than that using standard tool. The feed affects surface roughness greatly, while the spindle speed affects surface very little.