The invention provides an IEEE802.15.4 network asynchronous MPR throughput optimization method. Network source nodes simultaneously transmit data packets whose packet lengths obey geometric distribution to a destination node, the destination node can successfully receive a plurality of data packets simultaneously based on an asynchronous MPR mechanism, the node number in the current channel is detected after each source node completes backoff, a transmission or backoff again policy is made after a preset detection threshold is compared, and the network throughput and the reliability can be effectively improved.