Time synchronization technology is critical to the normal work and operational efficiency of wireless sensor networks. It’s an indispensable part. The traditional time synchronization algorithm is mainly used for time delay during node packet transmission and offset and drift of the node clock. But due to the influence of many complicated factors, the synchronization accuracy is not very high. So this paper uses time division multiple access (TDMA) technology for time synchronization of wireless sensor networks. The gateway node sends a beacon to notify each node of the time slot allocation. Simultaneously, those nodes that are not within the communication radius of the gateway use node listening to obtain the time slot situation. Each node sends a message in its assigned slot. Finally, the TDMA protocol of the media access control （MAC) sublayer is combined with tree cluster tree protocol (CTP) to analyze the effect of the proposed method by calculating the packet loss rate. The experimental results show that the packet loss rate decreases significantly after TDMA is applied, indicating that TDMA has a good effect on time synchronization.