The invention relates to a vane calibrating device used for a wind generating set. The vane calibrating device comprises a vane clamp and a direction sensor, a control surface of a vane is fixed in a straight groove in the lower portion of a Y-shaped groove and is overlapped with an N-S connecting line of the vane, the direction sensor is arranged in a V-shaped groove in the upper portion of the Y-shaped groove, and collects the direction of a main shaft of a blower fan via a collection point and records the angular displacement in the process that the collection point is moved to the Y-shaped groove, and the collection point is positioned in an axis or groove or sideline in parallel with the main shaft of the blower fan. The direction sensor can obtain a direction vector of the N-S connecting line, the direction vector is compared with a direction vector, obtained by the collection point, of the main shaft of the wind generating set, the direction sensor calculates a deviation angle of the N-S connecting line relative to the main shaft in the horizontal plane, and the vane is calibrated according to the deviation angle. The invention also relates to a vane calibrating method used for the wind generating set.