Abstract: The MTB composed of both boundary scan chips and non-boundary scan devices will be existing for a long time.Clusters Testing of non-boundary scan devices in MTB is a very important and practical problem.In order to reduce the test time of clusters in MTB，a technique of optimal configuring multiple boundary scan chains is presented based on the greedy strategy and the sorting technique of single boundary scan chain.The examples show that this technique can increase the test efficiency significantly.