In this paper the comparative study of a cooperative communication system is analyzed under single and two-relay as well as different diversity protocol. The single and two relays with two retransmission protocols amplify and forward (AAF) and decode and forward (DAF) are implemented as well as four diversity combining techniques such as equal ratio combining (ERC), fixed ratio combining (FRC), signal to noise ratio combining (SNRC) and equal signal to noise ratio combining (ESNRC) are used at the destination for each protocol. When ERC or FRC is implemented for both AAF and DAF diversity protocols the two-relay system presents better performance compared to the single relay. On the other hand, two-relay cooperative system has shown improved system performance at lower SNRs for SNRC or ESNRC. The proposed two relays system using cooperative diversity can achieve remarkable benefits in wireless transmission and the performance can be enhanced of the transferred signal with improved channel quality