水下传感器网络中时空不确定性严重,控制报文易发生冲突.时隙预约类MAC协议中控制报文发生冲突的概率较大,且节点位置变化会给报文接收带来不利影响.在此基础上提出了一种预设收发时间的水下MAC协议——PC-MAC.在PC-MAC协议中,考虑到发送节点位置可能出现变化,接收节点将预先设定接收报文的时间窗口,发送节点以接收窗口为依据,计算报文的发送时刻,从而避免报文冲突.仿真实验表明,根据网络的数据流量合理设定PC-MAC协议的参数,可获得较为理想的网络性能. Under the condition of underwater sensor network, the space-time uncertainty is serious, and the control messages are prone to conflict. The collision probability of the control messages in the time-slot booking MAC protocol is large, and the change of the node position will adversely affect the message reception. Based on this, an underwater MAC protocol, PC-MAC, which presets the sending and receiving time is proposed.In the PC-MAC protocol, considering the possible change of sending node location, the receiving node will preset the time window of receiving message , The sending node calculates the sending time of the packet based on the receiving window and avoids the packet collision.The simulation results show that the optimal network performance can be obtained by setting the parameters of the PC-MAC protocol according to the data traffic of the network.