Abstract: Physical-layer Network Coding (PNC) is an efficient approach that can improve the system spectrum efficiency by allowing two different nodes to transmit their information to a common node simultaneously which can save more time slot resource compared with Network Coding (NC). In this study, for the purpose of further improving the performance of cooperative networks, a new cooperative diversity scheme which combines Decode-and-forward (DF) protocol and physical-layer network coding, is proposed for a two-hop cooperative system with multiuser. In the proposed scheme, users broadcast their information using quadrature carriers simultaneously and the relay node employs decode-and-forward mode. To check its validity, the Bit Error Rate (BER) and throughput of the proposed scheme, under different propagation cases, are investigated and compared with that of traditional decode-and-forward. The simulation results reveal that the proposed scheme can effectively improve the system performances.