Fractographic examinations were performed on crack initiation sites for 10%SiC particulate reinforced aluminum cast alloy. Rotating-bending fatigue test were conducted in air and RT. Stereo imaging technique was applied to examine 3D shape of the fatigue crack initiation sites. Based on the observation results a mechanism of fatigue crack initiation for this material was constructed and a model to predict fatigue life of 10%SiC particulate reinforced aluminum cast alloy was proposed using linear fracture mechanics.