In this thesis, we sort the patterns of transition delay fault (TDF) for low power testing. These patterns need only a part of flip-flops to do shift, launch and capture operations. We analyze the relationship between test patterns, choose one test pattern that can be connected after a target pattern, and fill suitable values to complete the sorting process of test patterns. We experiment the patterns for ISCAS’89 circuits. The results show that the proposed method can reduce test power and have better fault coverage than original test patterns.