The invention relates to a sealing device for the low-impact spatial docking of a spacecraft. The sealing device comprises a target aircraft docking sealing structure and a tracking aircraft docking sealing structure, the structures of the target aircraft docking sealing structure and the tracking aircraft docking sealing structure are the same and comprise front-mounted sealing members, rear-mounted sealing members, maintaining frames, fastening members and plane flanges, wherein the maintaining frames are connected with the plane flanges through the fastening members, the rear-mounted sealing members are installed on the sides, in contact with the plane flanges, of the maintaining frames, and the front-mounted sealing members are installed on the sides, used for docking, of the maintaining frames. The sealing device has the advantages that the sealing demands on a docking surface of a spatial-docking aircraft low-impact docking system can be met, the load is low, the docking is easy,the separation is easy, redundant sealing is achieved, and recycling is achieved.