A reciprocating washer for a water supply pipeline is disclosed, and relates to a washer for the water supply pipeline to solve the problem that ''growth ring'' is the current water supply pipeline cannot be removed effectively. Automatic exhaust devices are respectively arranged at the front and back ends of the pipeline to be washed. An air compressor is connected with a pulse generator. The pulse generator is provided with two exit pipes inserted into a water inlet pipe and a water outlet tube respectively and the pulse generator is communicated with the pipeline to be washed. A water inlet controller and a water inlet pressure transmitter are connected with the water inlet pipe; an exhaust controller and an exhaust pressure transmitter are connected with the exit pipe of the pulse generator. A water outlet controller and a water outlet pressure transmitter are connected with the water outlet pipe. The detection signal input ends of a central control circuit is respectively connected with the output ends of the pressure transmitters; the control output ends of the central control circuit are respectively connected with the input ends of the controllers. A control signal output end of a pulse controller is connected with a control signal input end of the pulse controller. The invention is mainly used to wash the water supply pipeline and can remove 80% of ''growth ring'' in the water supply pipe network.