In this paper, an adaptive relay scheme of hybrid relay system is proposed based on channel state information of the received signal-to-noise ratio (SNR) at the relay node. hybrid relay system is comprised of amplify-and-forward, decode-and-forward and demodulate-and-forward together in cooperative networks. The relay protocols are selected adaptively, on the basis of power allocation (PA) constraint, or the SNR value at previous hop. Thus multihop performance of the relay system can be improved by applying PA allocation scheme. The simulation results show that the performance of the novel hybrid relay protocol can be improved significantly compared to the conventional hybrid system in terms of error performance and link efficiency.