A method of searching for and sorting failure signatures of wafers is provided. First, a failure signature database is built up for recording a plurality of failure signature data, wherein each failure signature data includes a failure signature, a location field for the faulty dies, a failure mode, a position dependence information and a dependent signature. Next, a selected wafer is tested and a test result is generated. Last, a comparison result is generated by an automatic comparing device, wherein the comparison result includes a hit or a miss. When the comparison result is a hit, the comparison result further includes a hit ratio. And as the hit ratio exceeds a predetermined value, the step of comparing the dependent signature of the failure signature database is skipped.