Based on the static threepoint calibration method of wind direction sensors, an evaluating method of measurement uncertainty for calibration results about wind direction sensors of automatic weather stations is introduced. The purpose is to ensure the accurate, reliable and credible observation data of wind direction sensors. In this paper, according to the requirement of the “Calibration Method of Wind Direction of Automatic Meteorological Station” and JJF10591—2012 “Evaluation an Expression of Uncertainty in Measurement,” ten repeated tests are designed for the three calibration points of wind direction, and the sample standard deviation is merged to evaluate the uncertainty of Type A. The uncertainty sources of Type B in the calibration process are analyzed, and the uncertainty of Type B is evaluated. Finally, the extended uncertainty is obtained by combining the uncertainties of Type A and Type B. The evaluation method can provide a reference for evaluating the reliability of calibration results of wind direction sensors.