The invention relates to a half-embedded flexible water supply pipeline cleaning device and a descaling method used for water supply pipeline cleaning through the half-embedded flexible water supply pipeline cleaning device, and belongs to the technical field of pipeline engineering in the municipal engineering discipline. In order to promote the water supply pipeline cleaning technology to be applied to the engineering field, needle-shaped flexible padding chains are pulled to a water supply pipeline to be cleaned and fixedly connected with the water supply pipeline to be cleaned, a forced circulation pump is started to enable water to form violent turbulent flow in the pipeline, and the surfaces of the needle-shaped flexible padding chains and the inner wall of the water supply pipeline generate a friction scrubbing effect; meanwhile, pulse air pressure is introduced into the pipeline, under the solid-liquid-gas three phase coupling cleaning effect, pipeline scale is cleaned away and discharged from a residue discharge port, and the purpose of cleaning the water supply pipeline is realized. The half-embedded flexible water supply pipeline cleaning device and the descaling method have the advantages that the automation degree is high, control precision is high, 30%-40% of water is saved compared with traditional methods, and 20-25% of time is saved; in addition, the pipeline is free of damage, and safety and environment-friendliness are achieved.