It is increasingly a difficult problem of how to decrease the usage of network resources by network management systems. Otherwise, the performance of network management is affected by the scheme to collect MIB (management information base) information. A new algorithm, GPA (group-prefetching algorithm), is put forward, which is used for retrieving MIB information from the managed devices in heterogeneous WAN (wide area network). GPA can adjust many little retrieving objects into one prefetching group to access,decrease the frequency of retrieval,and thus can use fewer network resources and decrease the network overhead without alteration of the existing network management protocols.