Amplitude measurement uncertainty of high voltage pulse lies in the probe and oscillograph measurement. A D-dot probe has been designed to measure the voltage pulse at the input of a high-power triplate transmission line for the prototype of Z-pinch primary test stand. The uncertainty sources were analyzed. Type A evaluation of standard uncertainty was used to evaluate the random effect in calibration of the D-dot probe and the resistor divider. Type B evaluation of standard uncertainty was used to evaluate the random effect in measurement, the systematic effect of the calibration, and the uncertainty from the resolving ability of the oscillograph. The uncertainty of the attenuator and the oscillograph themselves are refer to the calibration document. The output waveform of the resistor di