Al/SiCp composite material is rapidly advanced due to its applications to weapon, military, aeronautics and astronautics. In some cases, fields of research are stagnating for its difficulty in material processing. In this study, we are particularly concerned about the cutting mechanism of Al/SiCp through modeling and simulations on wear rate of the tools. These simulations of tool wear rate and cutting mechanism of Al/SiCp are proved by cutting tests on Al/SiCp with nanocemented carbide tool WC-7Co and common cemented carbide tool YG8. A detailed investigation suggests that the cutting instinct of Al/SiCp is of interrupted cutting process. And the grain loss, less tipping and blade fracture during tool wear results from high frequency intermittent shock by SiC grain. The wear behavior on the tool flank is mainly of grain loss. However, the wear behavior of the rake face is not only of grain loss, but also abrasive wear of WC grain by SiC grain. It is conclusively demonstrated that the model of tool wear rate is sufficient for revolution characterization of tool wear rate on grain size, volume fraction of reinforcement, and also significantly important to prove the interrupted cutting process mechanism of Al/SiCp.