Abstract: To explore allocation strategy of network coupling strength for improving performance of power grids, we analyze synchronizability of power grids by using critical synchronization coupling strength, and compare robustness of power grids by imposing disturbance power on network nodes. It is found that local topological structure and power of nodes in power grids restrict the local synchronizability of nodes. In general, the greater the power and the smaller the degree value of the node, the weaker its local synchronizability is. And it is more difficult for the node to reach a local synchronization state with its neighbors. Based on this, a non-uniform distribution strategy of network coupling strength is proposed. Keep the total coupling strength the same, we increase the coupling strength between nodes with weak local synchronizability, and reduce the coupling strength between nodes with strong local synchronizability. It shows that this method optimizes synchronizability of the network and enhance robust performance of power grids to a certain extent.