Abstract: This invention relates to a method for entire removal of a space truss, and an assistive support mechanism therefor. The assistive support mechanism is arranged on a vertical support rod of a truss structure, the assistive support mechanism comprises an assistive support assembly, a lattice support member, and a conversion platform. The lifting assembly is arranged at a top of the conversion platform and comprises a stranded wire, a lifting member, and a control member. The method for entire removal of a space truss comprises mounting the assistive support mechanism, and performing initial removal of the truss structure; lowering the truss structure; and then performing secondary removal of the entire space truss. The major removal work is done on the ground, thereby reducing the requirement for removal-assisting measures and the operational risks, and improving the working efficiency.