Pulse-Radiation field integral technology measures the power density distribution by moving a single receiving antenna or field sensor which covers the radiation area of pulse power source, and the total radiation power could be calculated by integration. This method provides an effective testing tool for evaluating pulse power source levels, which could solve the traceability problem of microwave device under large-power conditions through spatial attenuation. This letter introduced pulse power calibration method based on radiation field integral algorithm, and then analyzed factors which affected the measurement results, and it would improve the measurement accuracy of radiation field integral algorithm.