Abstract: Test generation method for the small delay defects (SDDs) not only requires low algorithm complexity,but also more possibility to detect small delay．Faster than at-speed testing avoids to detect the longest sensitization paths for poor efficiency.It requires test patterns to be delicately classified into groups according to the delay of sensitization paths,and each group is managed to be applied at certain clock frequency.Then it adopts a path selection method to identify a certain length of paths quickly and accurately,which can achieve high test quality.At the same time,the paper firstly proposed that choosing single path sensitization criterion for short paths and nonrobust sensitization criterion for the critical paths to test can improve transition delay fault coverage (TDF) of the nodes which contain small delay defects at the cost of a little of time compared with adopting single sensitization criterion.Experimental results on ISCAS’89benchmark circuits show that the proposed method can achieve higher transition delay fault coverage of SDDs with low CPU time.