The invention relates to a relay operating-power automatic measuring instrument. The automatic measuring instrument is provided with a control panel, the control panel is provided with four wiring terminals and buttons, a circuit board is installed in a box body, a programmable power-supply module and a single-chip microcomputer controller are installed on the circuit board, the circuit board is further provided with a dithering elimination circuit, the single-chip microcomputer controller is connected with the programmable power-supply module by a serial port, the first and second wiring terminals on the control panel are connected with the programmable power-supply module, and used as output ports of direct voltage for connecting coils of a tested relay, the output end of the dithering elimination circuit is connected to the single-chip microcomputer controller, the input end of the dithering elimination circuit is connected to the third and fourth wiring terminals for connecting normally open contact of the tested relay and feeding back operating information of the tested relay, and the buttons are connected with the single-chip microcomputer controller by wires. The automatic measuring instrument can meet the requirements of various intermediate relays and outlet and tripping relays in secondary circuit.