The invention relates to a leakage protection switch and step voltage detection device tester, which comprises a shell, a circuit board is arranged in the shell, and a main controller, a power amplifier, a memory, a resistive load and an AC-DC-AC module are arranged on the circuit board; the circuit board is connected with the display module, the adjusting module and the output port on the shell,and is connected with the B-type leakage protection switch or the step voltage detection device through the output port. According to the invention, the display module can select waveform signals in the memory through the main controller, provide energy for the waveform signals through the power amplifier, convert the waveform signals into current through the resistive load and output the currentto the B-type electric leakage protection switch, thereby detecting the B-type electric leakage protection switch. Furthermore, the adjusting module can control the AC-DC-AC module to convert 220V alternating current into direct current through the main controller, then the direct current is inverted into alternating current, meanwhile, after the phase, frequency and voltage value of the alternating current are changed, the alternating current is output to the step voltage detection device through the resistive load, and then the step voltage detection device is detected.