Abstract: This paper deals with the effects of hot water immersion and accelerated weather aging on the mechanical properties of polyphenylene sulfide (PPS) composites hybrid rainforc.:d with carbon fibre(CF) and glass fibre (GF). The tensile and flexible strength of these composites roughly conform to the mixture law,however they show different susecptablities to these two aging procedures.The strength retention of composites after aging is related to the aging mode an d the nature of fibres.