Abstract: EDM machine tool is a special machine tool for processing conductive material by using EDM principle. To avoid broken wires when feeding the electrode wire in the process of machining. First, the electrode wire was simplified as an Euler-Bernoulli beam, and a generalized calculation model for the critical frictional force and critical cone angle of the electrode wire was established. Then, the tungsten electrode wire with a diameter of 0.19 mm and a length of 63 mm was taken as an example to obtain the critical frictional force and the critical cone angle, and the accuracy of the model was verified by the friction test. Finally, the accuracy of the model was verified by the friction test. Using this model and its calculation results can effectively avoid wire breakage of wire electrode and guide the adjustment of electrode taper.