The invention discloses a telescopic-arm blocking crossing rack, and belongs to the technical field of power line engineering. The telescopic-arm blocking crossing rack comprises rack bodies and blocking devices, wherein the rack bodies are arranged at two sides of a crossed object, the blocking devices are connected to the rack bodies, each rack body comprises a vertical post, a rotation support seat, a mast and rack body fixing pull lines, the vertical posts are arranged at the two sides of the crossed object and are fixed by the rack body fixing pull lines, the rotation support seat is connected between the mast and the vertical post, each blocking device comprises a telescopic arm, a balancing arm and a blocking rod system, the telescopic arm and the balancing arm are respectively and symmetrically arranged at two sides of the rotation support seat, a blocking rod system is attached onto the telescopic arm, and the blocking devices at the two sides of the crossed object are abutted in the air by the telescopic arms. By the telescopic-arm blocking crossing rack, rapid blocking can be achieved in the air, the blocking power-failure running time is short, a bearing framework crossed by blocking is of a rigid structure and is high in stability, the crossed object can be protected very well, meanwhile, broken line impact can be borne, the crossed object is protected within the rigid framework, and the safety guarantee during circuit crossing is improved.