In order to reduce the packet loss rate in wireless sensor networks, a data transmission compensation mechanism based on network coding ～is put forth. On the basis of traditional star topology, a new cooperation node is designed and integrated into the mechanism. The cooperation node generates a coding packet by coding the packets from the acquisition nodes and sending the coding packet to the base-station. PC compensates the data loss of acquisition nodes through the data from the base-station. The node calculation assumption is reduced by deterministic coding. The validity of time when the cooperation node sends packets is guaranteed by applying the event trigger mechanism. Moreover, to ensure reliable and real-time data collection, the mechanism adopts time division multiple access (TDMA). The experimental results show a stable performance of the cooperation node, correct decoding of PC and effective reduction of the packet loss rate.