A crimping tool with detachable cable connector tester includes a crimper body for crimping a signal connector to a cable, two pressing handles, and at least one cable connector tester. Therein, the two pressing handles are movably connected with the crimper body and have at least one fastening groove, the cable connector tester is detachably set in the fastening groove, and thereby construction workers can use the crimping tool to crimp the signal connector with the cable. After crimping, the signal connector can be inserted into the cable connector tester that is selectively attached with the crimping tool, so as to test the conduction between the signal connector and the cable.