In order to study the formation principle of obstructing phenomenon and its influence on the results of wind speed calibration, this paper establishes the flow field simulation models of meteorological wind speed calibration for different blockage ratio. The influence of different blockage ratio conditions on the flow field of cylindrical and cuboid wind tunnel test section is simulated. The existing theoretical model and comparison method adopt a single correction coefficient to correct the wind speed indication value at all calibration points, which leads to deviation in the correction of low. With this in mind, a piecewise correction method is proposed to calculate the blocking correction coefficient independently for each calibration point. Combined with the anemometer calibration data of EC9-1, EL15-1A and ZQZ-TF, the influence of the piecewise correction method and the existing methods on the anemometer measurement characteristics of is compared. The experimental results indicate that the three obstruction correction methods can improve the measurement characteristics of anemometer, such as measurement error and frequency equation, which makes the indexes of slope, intercept, indicating value and frequency equation of anemometers are closer to the calibration data in standard wind tunnel. The piecewise correction method has the most significant effect on improving the overall deviation degree of the three types of anemometers. The deviation degree of the anemometer corrected by the piecewise correction method is closest to the value measured by the standard wind tunnel.