The invention provides a drilling tool outside thread stress detection device. The device comprises a conical disc, a detection mechanism and a transmission mechanism. The detection mechanism comprises multiple detectors. Each one of the detectors comprises guide rods arranged along a circumferential direction of the conical disc and metal magnetic memory sensors arranged on the guide rods. The transmission mechanism is connected to the guide rods and drives the metal magnetic memory sensors to move along the cone element of the outside threads of the drilling tool. The metal magnetic memory sensors fitting to the outside thread conical surface of the drilling tool are arranged and move along the cone element of the outside threads of the drilling tool so that an accurate drilling tool outside thread magnetic memory signal is acquired. According to a metal magnetic memory detection principle, diagnosis of drilling tool outside thread defects and a stress concentration zone is realized. The drilling tool outside thread stress detection device provides accurate basis for early stage flaw detection of a drilling tool.