The invention discloses a gate valve which comprises a valve body. A main valve plate is arranged on the valve body in a penetrating mode; a sliding way used for sliding of the main valve plate is formed in the valve body and fixedly connected with a sealing ring; a main screw rod in threaded connection with the main valve plate is arranged on the main valve plate in a penetrating mode; the main screw rod is connected with a bearing fixedly connected with the valve body in a sleeved mode; the main screw rod is connected with a main gear in a sleeved mode; the main gear is engaged with driven gears; a first driven screw rod fixedly connected with the corresponding driven gear is arranged on the driven gear in a penetrating mode; the first driven screw rod is sleeved with a first driven valve plate in threaded connection with the first driven screw rod; and the radius of the driven gears is smaller than that of the main gear, and the screw pitch of the first driven screw rod is larger than that of the main screw rod. The gate valve has the effects that a water flow is prevented from leaking from the main valve body, and multi-layer protection is achieved.