Novel building rainfall downpipe

The utility model relates to a novel building rainfall downpipe, which is arranged on the outer vertical surface of a building wall along the wall surface and comprises a dustproof net, clamping grooves, a downpipe body, threads, a water falling opening, a buffer pipe and a descaling agent, the dustproof net is arranged at the top of the water falling opening, the clamping grooves are arranged on two sides of the water falling opening, the descaling agent is placed in the clamping grooves, and the threads are arranged at two ends of the downpipe body. And the thread diameter of the upper end of each section of downpipe body is 1cm greater than that of the lower end of each section of downpipe body. Buffer pipes are arranged at the one-third positions of the bottoms of the downpipe bodies, and the downpipe bodies are screwed together through threads to form an integrated structure. According to the building rainfall downpipe, a thread splicing mode is adopted, and the design mode that the dustproof net and the