Abstract: Measuring high power microwave (HPM) power using a measurement system consisting of microwave receiving antenna, attenuator, diode detector, and waveform recording unit is a common method. In outdoor field (especially in winter）, due to the large temperature changes (usually up to 30-40 ℃), it inevitably leads to changes in the characteristics of the diode detector. How to effectively suppress the influence of changes in diode detector characteristics on pulse microwave power measurement is the key to improving the accuracy of HPM power measurement in outdoor field for such systems. This article discusses the principle of measuring pulse microwave power using the comparison method; In theory, it can be analyzed that the accuracy of measuring pulse microwave power using the comparison method is not affected by the temperature characteristics of the detector when the diode detector operates in the voltage power linear region. The experiment studied the relative deviation changes of the same pulse microwave power output from a pulse microwave source measured by direct detection method and comparison method under different temperature conditions of a diode detector. When the deviation of direct detection method for measuring pulse microwave power is 14%, the corresponding deviation of comparison method for measuring the same pulse microwave power is −5.3%. The measurement results show that using the comparison method can effectively reduce the influence of the temperature characteristics of diode detectors on the measurement of pulse microwave power.