Abstract: A crossbow has a stock assembly and a bow assembly. The stock assembly has a body, a retainer and a buffering spacer. The retainer is made of hardened plastic and has a vibrating frequency, a bolt groove, a mounting hole and a holding protrusion. The buffering spacer is made of hardened plastic and has a shape corresponding to the retainer, a vibrating frequency different from the vibrating frequency of the retainer, a gap, a through hole and a holding hole. The bow assembly is securely connected to the stock assembly and has a mounting base, two bow arms, a bowstring and a fastener. The different vibrating frequencies between the buffering spacer and the retainer can destroy the transmission of the shock wave between the retainer and the buffering spacer to disperse and reduce the impact force of the crossbow after shooting a bolt.