One of the key technologies in smart grid is an efficient, reliable and secure two-way communication system for meter data collection. Forming wireless mesh network with advanced electricity devices (smart meters), which have the communication capabilities for meter data collection, faces challenge on network communication performance caused by application layer data traffic. When a large number of data occur in emergence, the smart meter near the local LAN gateway faces great communicaton pressure, and it probably leads to extreme data congestion. Therefore, a new traffic scheduling algorithm is proposed based on the idea of the joint of muti-gateway to release the congestion of system. First, the muti-gateway mesh network is analyzed to study the main factors affecting network performance. Second, a new traffic scheduling algorithm is proposed with the idea of weighted queue of node. Simulation data show that compared with other algorithms, the new algorithm can release significantly the congestion of burst data, and it reduces effectively the latency and obtains a good balance among the throughput of the system gateways, which can improve the network communication performance.