As the traditional medium access control（MAC） protocols allow only one pair of nodes to communicate in a neighborhood of distributed single-channel Ad hoc networks,serious collision,low throughput and large delay may occur in this kind of network.In order to solve these problems,a novel MAC protocol based on the multi-packet reception（MPR） of multiple-input multiple-output（MIMO） system is proposed.In this protocol,both the binary-backoff and the share-backoff mechanisms are used to reserve and share the physical channels,thus realizing the multipoint-to-point communication in distributed single-channel Ad hoc networks and significantly improving the network throughput.A mathematical model of the normalized saturation throughput is also established for the new protocol.Theoretical and simulated results indicate that the proposed protocol outperforms the CSMA/CA（k） protocol based on the Bell Laboratories layered space-time（BLAST） coding in terms of network throughput.