The disclosure provides a water channel assembly including a channel shell and a filtering piece. The water channel is disposed on the surface of a cleaning roller in a seal and overturn mode so that the cleaning roller is washed by water flowing in the water channel. The filtering piece is laid in the water channel and faces the surface of the cleaning roller. As a result, the solid trash on the cleaning roller is filtered by the filter element and cannot enter the water channel, thus preventing the blockage of the waterway of the water supply system.