The invention relates to a clamp for processing a vertical positioning surface of a tail wing of an airplane. The clamp comprises a bracket, and a gesture adjusting positioning device which is positioned at one side of the bracket and used for providing positioning supporting to the medium tail part of the tail wing; external supporting devices for compressing the outer side of the head part of the tail wing are mounted on an upper cross beam and a lower cross beam of the bracket; an inner supporting device for compressing the inner side of the head part of the tail wing is mounted on a medium cross beam of the bracket; a main clamping mechanism for fixing the head part of the tail wing is also mounted on the bracket. With the adoption of the clamp, the vertical positioning surface can be automatically positioned and clamped; the requirement on positioning and assembling of large and poor-rigidity parts can be met; after gesture adjusting, the clamping effect is outstanding; the parts are free of deformation due to clamping; the adjusting efficiency is high; the adjusting is flexible and stable.