The invention discloses a rail-mounted water spraying device for municipal administration and relates to the technical field of water spraying equipment for municipal administration. The rail-mounted water spraying device for municipal administration comprises a main pipeline, a C-shaped supporting frame installed on the inner wall of the main pipeline, and a traveling mechanism installed on the outer wall of the main pipeline. Through holes are evenly formed in the positions, corresponding to the C-shaped supporting frame, of the pipe wall of the main pipeline in the length direction. In the main pipeline, each through hole is provided with a taper plug in a sealed fit mode. A rack is installed on the outer wall of the main pipeline in the length direction. The traveling mechanism comprises a supporting hoop, a power device installed on the left side of the supporting hoop, an ejecting device installed on the right side of the supporting hoop, and a control cabinet installed on the top of the supporting hoop. The ejecting device comprises a sliding sealing block installed at the lower right end of the supporting hoop. A water collection groove is formed in the middle of the concave arc face. A guide tube communicating with the water collection groove is formed in the outer side face of the sliding sealing block. According to the rail-mounted water spraying device for municipal administration, water is sprayed evenly, the stable water pressure can be maintained, and no area is left.