The invention relates to the field of non-linear photoconductive semiconductor switch parameter testing, in particular to a non-linear photoconductive semiconductor switch testing device and method. The non-linear photoconductive semiconductor switch testing device and method are provided for solving the problems existing in the prior art. Through cooperation of a delay synchronous machine, a laser, an optical fiber, a photoelectric probe, a first high-voltage probe and the like, the difficulty of conducting accurate testing on a non-linear photoconductive semiconductor switch on the high-voltage, high-current and ultrafast-pulse conditions is overcome, and accurate, convenient and reliable testing of the parameters such as the conduction delay time, jittering, the conduction resistance, the withstand voltage and the service life of the non-linear photoconductive semiconductor switch is realized. The device comprises the delay synchronous machine, the laser, the optical fiber, the photoelectric probe, high-voltage probes, an oscilloscope, a high-voltage pulse power source, Blumlein transmission wires, a matching load, an organic glass box, transformer insulating oil and limiting fixtures. The non-linear photoconductive semiconductor switch to be tested, the Blumlein transmission wires and the matching load are placed in the organic glass box and are immersed in the transformer insulating oil.