The invention provides a device and method for measuring thermosetting resin breakdown field strength. The device comprises a supporting frame, an upper electrode, a lower electrode, a thermosetting resin groove and a distance fixing rod, the supporting frame is formed by the upper plate and the lower plate which are arranged horizontally and supporting rods which are vertically arranged on two sides of the upper plate and the lower plate, the thermosetting resin groove is positioned in the lower plate, and the distance fixing rod is positioned at one end of the upper electrode and vertically penetrates the upper plate. The device can effectively prevent creepage and is simple to operate and easy in realization, accuracy of thermosetting resin sample thickness is improved, and measuring errors are reduced.