The invention discloses a first rain abandonment device, which is characterized in that it is a first rain abandonment device, which is characterized in that it includes a well body and a water inlet pipe, an outlet pipe and an abandonment pipe arranged horizontally on the well body, The height of the jettison pipe is lower than the water outlet pipe, the well body is provided with a filtering device at the water outlet pipe, and the well body is provided with a buoy restrictor valve at the discard pipe; the buoy restrictor valve includes a mounting plate, The pipe cover, the buoy and the rod-shaped connector hinged with the mounting plate, the pipe cover and the buoy are connected to the end of the rod-shaped connector and are located on both sides of the jettison in the initial state, and the two sides of the rod-shaped connector are respectively set There are an initial state regulating device and a closing limit device, and the buoy restrictor valve is connected with the well body through a mounting plate. The invention is simple in structure, easy to install, can complete the automatic discharge of pollutants in the early stage, and filter the collected rainwater in the later stage, without the need for electric devices, and is safe, environmentally friendly, energy-saving and durable.