The invention proposes a method for measuring an MOS threshold voltage of a CMOS inverter, so that a technical problem that an NMOS threshold voltage and a PMOS threshold voltage inside a packaged CMOS inverter can not be measured simultaneously in the prior art is solved. The method comprises: a direct-current voltage source applies a direct-current voltage to a CMOS inverter and a signal generator applies a pulse signal to the CMOS inverter; a dual-channel oscilloscope collects an input voltage and an output voltage of the CMOS inverter simultaneously; a static voltage transfer curve of the CMOS inverter within one cycle is drawn; a gain of a conversion point of the static voltage transfer curve is calculated; a straight conversion point gain line is drawn; end points of an overlapped zone of the straight conversion point gain line and the static voltage transfer curve are calculated; and a threshold voltage Vthn of the NMOS and a threshold voltage Vthp of the PMOS are obtained. The method having advantages of high measuring efficiency and high universality is suitable for a digital circuit design as well as extraction and analysis of threshold voltages in simulation.