Nowadays, composite material is more and more popular mainly because of its low density and high strength. This paper focuses on experimental research of coarse milling process of carbon fiber reinforced carbon matrix composite (C/C composite) in low spindle speed and large milling depth. The milling force prediction model for milling of composite using the end milling cutter is built by orthogonal experiment. Experiment test shows that the results predicted by the proposed model are in well agreement with measured ones and the milling force increases with the increment of feed per tooth, milling depth and milling width, and the effect of milling speed on milling force is not very obvious. In addition, machining accuracy and quality of machined surface is difficult to satisfactory, because of the existence of the substrate lacunas and carbon fibers in C/C composite, by using the existing ordinary material surface integrity evaluation method.