The calibration results of vertical-pointing Ka band millimeter wave radar, which is short for MWR,directly determine the accuracy of detection data, affecting the application of the product in meteorological service. The calibration scheme is developed according to the vertical-pointing MWR features, controlling the unmanned aerial vehicles to hover at different heights. The values of distance, reflectivity factor, linear depolarization ratio and radial velocity of metal sphere in the radar beam are obtained. By analyzing the calibration data, distance deviation of MWR between the measured and calculated values is 2.15 m at most and 0.1 m at least; horizontal and vertical reflectivity factor deviation is 2.52/ 2.56 dB at most and 0.85/1.18 dB at least; radial velocity deviation of MWR and GPS is 0.014 m/s at most and 0.002 m/s at least. The detection parameters are adjusted according to calibration results to reduce the detection error from the radar equipment.