The invention, which relates to the technical field of the semiconductors, provides a voltage measuring method and a voltage measuring circuit. The method comprises the following steps that: accordingto a potential of a grid electrode of an NMOS transistor, a first voltage and a second voltage are acquired, wherein the first voltage and the second voltage are potentials between a first voltage divider resistance and a second voltage divider resistance when the potential of the grid electrode of the NMOS transistor is in different states; and calculation is carried out based on the first voltage, the second voltage, and at least two voltage divider resistances to obtain current voltages at two ends of a light emitting diode. According to the invention, the first voltage and the second voltage are separately obtained in different voltage measuring circuits corresponding to different connection states and calculation is carried out by combining parameter values corresponding to the respective voltage divider resistances in the voltage measuring circuit, so that the current voltages at two ends of the light emitting diode are obtained. Therefore, a phenomenon of adding the divider resistance for detection in working of the light emitting diode is avoided; and the accuracy and flexibility of obtaining the current voltage are improved.