15% (volume fraction) SiC_p/8009Al metal matrix composites(MMCs) prepared by spray co-deposition were hot-extruded and rolled to investigate the effects of porosity and local SiC_p clusters on mechanical properties. The microstructures were examined by using optical microscopy(OM), scanning electron microscopy(SEM), X-ray diffractometry(XRD) and transmission electron microscopy(TEM). The mechanical properties were measured by tensile testing. The experimental results show that lamellar structure is composed of pores and SiC_p clusters and can be improved by secondary processing, enhancing mechanical properties. The main strengthening mechanism and fracture behavior of MMCs were discussed too.