The invention discloses a well lid with the drainage amount adjusting function. The well lid comprises a well seat and a well lid body and is characterized in that the well lid body is provided with multiple through holes, threaded rods are arranged in the through holes, and the lower ends of the threaded rods are connected with the well seat in a threaded fit manner; the portions, between the bottom face of the well lid body and the threaded rod penetrating face of the well seat, of the threaded rods are sleeved with springs; the well seat is provided with an annular iron block; the well lid body is provided with an annular groove matched with the annular iron block and an electromagnetic layer is arranged on the surface of the annular groove; and the well lid body is provided with a cipherer and an electric cabinet, the cipherer is connected with the electric cabinet, and the electric cabinet is connected with the electromagnetic layer through a circuit. By the adoption of the well lid, accumulated water can be rapidly drained.