In order to reduce the effect of error propagation in the process of cooperative communication in wireless sensor networks (WSNs), we propose a reliable transmission mechanism based on opportunistic error correction. First, three cooperative transmission schemes are proposed in the multinode cooperative WSNs, and the model of the cooperative error propagation is established based on channel quality and the symbol error rate. Then, aiming at the cooperative error, such as merging, scheduling, and interference, we propose an opportunistic error correction algorithm based on the channel, source and cooperative networks. Finally, based on the above conclusions, and taking the performance requirements of users, the complexity of scheduling and the model of cooperative communication into account, we propose an opportunity reliable transmission scheme. The results of mathematical analysis not only verify the higher reliability of the proposal than the static mechanism, but also prove its superior performance in real time, reliability, throughput and energy efficiency in end to end communications.