The application discloses a method and device for determining pulse modulation signal phase spectrum, and computer equipment, and relates to the field of the signal processing. The problems that the operation is troublesome and the accuracy is low when calibrating measurement equipment by using a high-speed narrow pulse standard signal can be effectively solved. The method comprises the followingsteps: acquiring an amplitude spectrum measurement value, a target duty cycle and a scaling factor of a to-be-measured pulse modulation signal; computing an amplitude spectrum distortion result of theto-be-measured pulse modulation signal according to the amplitude spectrum measurement value and the target duty cycle; estimating a phase spectrum distortion estimation value of the to-be-measured pulse modulation signal according to the amplitude spectrum distortion result and the scaling factor; determining a phase spectrum actual value of the to-be-measured pulse modulation signal by utilizing the phase spectrum distortion estimation value, thereby determining the to-be-measured pulse modulation signal as the standard signal to calibrate the measurement instrument based on the phase spectrum actual value. The method disclosed by the application is suitable for determining the pulse modulation signal phase spectrum.