The hole-set method is one of the most widely-used methods for measuring the divergence angle of airborne laser detection system in the process of alignment and inspection.In view of such factors as the quality of incident beam, sensitivity of power meter and positioning accuracy of the stop, errors will occur between the measured value and the real value of the divergence angle.In this paper, the theory of laser transmission and transformation is adopted to analyze the influence of the above-mentioned factors on the measurement results.Our findings can provide instructions for the selection of such parameters as the diameter of the stop, the focal length of the lenses, sensitivity of power meter and positioning accuracy of the stop in the process of divergence angle measurement, so as to reduce the measurement error and improve the measurement accuracy.