In MapReduce environment, problem of data redundancy, a large number of tasks to be processing and mass data storage come up, in order to solve these problems, we put forward the way of data prefetching, preprocessing of hid the remote data access latency, by adjusting the allocation of resources to Reduce the business, we put forward the method of than before, caused by the Reduce tasks of remote data access performance problems caused by time delay and resource competition system, the hidden by prefetching data the method Reduce task of remote data access latency, and Reduce task control through the resource allocation, to Reduce resource competition caused the Reduce task, the experiment results show that with the default Hadoop graphs and Hadoop Online Prototype (HOP), compared with the method the system performance can be improved by more than 10%.