Efficient data access is one way of improving the performance of the data grid. In order to speed up the data access and reduce bandwidth consumption, data grid replicates essential data in multiple locations. This paper studies data replication strategy in data grid, taking into account two important issues which bound the replication: storage capability of different nodes and the bandwidth between these nodes. We propose a new dynamic replication strategy based on the principle of local optimization. The data grid can achieve the global data access optimization through the interaction of the local optimization in the local optimization areas.