To solve this problem of wire broken in WEDM, a novel protection method for dual guide wheel was presented based on summarizing and analyzing the principles and characteristics of the methods of signal feedback, mechanical trigger, current onoff.The corresponding wire breaking protection device and control circuit were designed.Through the simulation of the electrode wire on the cantilever beam by ANSYS,the optimal installation position of the protection device was obtained.The simulation and experiment show that the design of the wire broken protection device can effectively reduce the wear of the electrode wire, so that the force can be balanced, the vibration is weakened and the movement is more stable.The designed control circuit has the advantages of low error rate and high reliability.