The invention discloses a voltage measuring and displaying device, comprising: at least one voltage collecting circuit, which is composed of operational circuit connected with the control switch and voltage stabilizing circuit. The voltage signal measured by voltage collecting circuit is output to a singlechip for detecting the voltage signal. The voltage signal measured by singlechip is output to a level switching circuit, which outputs the voltage signal to a liquid crystal display to display the voltage value. The device detects each voltage of basic unit at real time, when one or several voltages is lower than the lowest operating voltage requirement, the alarm is timely sent and the voltage can be displayed on the liquid crystal display. The stabilizing circuit can effectively solve the problem that the test line on using generates high positive voltage or negative voltage due to unexpected turnoff to damage the electronic component.