SiCp/AZ61 composites reinforced with SiC particles were fabricated by semi-solid stirring-melt casting technique. The creep properties of the composites have been studied by dynamic mechanical thermal analysis, micro-structural and XRD observation. The results show that the matrix grains were refined obviously at high temperature with SiC particles introducing and the creep properties of SiCp/AZ61 composites were improved comparing with AZ61 alloy. SiC particles were substituted for Mg17Al12 phase that was easily intenerated at high temperature on grain boundaries. The pinning of SiC particles prevents dislocation and slip of grain boundary at high temperature.