Abstract: Motif is a very important information when analysis and mining for network.The exiting algorithm for it is used to transform the edge and vertex in original network under given conditions, and then, find all subgraph and get rid of the subgraph that don't follow the Motif require.The new algorithm in this paper is a pruning approach based bottom-up rather than don't using the transformation.First we find all minimum subgraph that follow the Motif require, and then deduce other big subgraph.All subgraph that find use the new algorithm is follow Motif require.And through time efficiency analysis concluded that for this problem, the new algorithm is superior to existing algorithms, has some theoretical research value.