Abstract: The volume fraction (V) effect of SiC particles On fatigue crack propagation in SiCp/Al composites has been investigated by fatigue propaga tion rate examination,as well as fatigue crack path and fatigue fracture surface observation.The results indicate that fatigue craclt propagation resistance (FCPR) of the composites as V increases.However,the FCPR of composites is superior to that of matrix only when V is greater than 15%.