Surface micro-morphology and roughness are considered as the important indexes of PBX turning surface quality. They affect the interface friction in assembly and transportation processes,and affect the adhesive strength of complicated structural PBX components. Different turning manners,such as dry turning and with cutting fluid,and different technological parameters were employed to make samples,which is a type of HMX based PBX. Observation tests of turning surface were established through 3D video optical microscopy and scanning electron microscopy (SEM). The results show that the turning surface consists of continual spiral barred regions,which include knifepoint-extrusion stripes and non- knifepoint-extrusion stripes. The former are planar,and the micro-cracks and cracked explosive particles can be discovered in the latter stripes. All these phenomena are obvious especially in the manner of turning with cutting fluid. Stylus profiler was used to detect the surface roughness. The results indicate the roughness increases with cutting depth,feed and revolutions of machine spindle. A surface roughness empirical formula was deducted based on experiments,which can forecast practical roughness under different cutting parameters.