Abstract: As a new composite processing technology, ultrasonic assisted micro-milling represents unique advantage in processing hard and brittle materials and composites. In order to solve the problems of difficult machining, high machining accuracy requirement and low processing efficiency in industrial applications of graphene-based aluminum matrix composites, a pure aluminum and graphene-based aluminum matrix composite were taken as research objects to carry out ultrasonic assisted micro-milling experiments for graphene-based aluminum matrix composites with different ratios. The effects of graphene content, feed rate per tooth and ultrasonic amplitude on milling force and surface roughness were analyzed based on orthogonal experiment, and the optimal process parameters of graphene aluminum matrix composite under ultrasonic assisted micro milling were determined. The results show that the graphene-Al matrix composites can put up a best processing performance under 1 μm/z feed per tooth and 3.05μm ultrasonic amplitude.