Composite sealing device for deformation joint of underground building

The invention relates to a composite sealing device for a deformation joint of an underground building. In order to overcome the defects in the prior art, the composite sealing device for the deformation joint of the underground building comprises a sealing cover plate, wherein flanges are arranged at the two sides of the sealing cover plate, a V-shaped deformation groove is formed in the middle of the sealing cover plate, the sealing cover plate comprises a left side plate, an upper plate and a right side plate, the upper end of the left side plate and the upper end of the right side plate are connected with the two ends of the upper plate separately, and a left inflation column and a right inflation column are arranged in the deformation joint; the left inflation column is located at the outer side of the left side plate, the right inflation column is located at the outer side of the right side plate, the lower end of the left inflation column and the lower end of the right inflation column abut against a b