The invention relates to an instantly shutoff valve which comprises a valve body and a valve rod. The valve body is provided with an upper cavity connector, a lower cavity connector and a valve rod mounting port. A valve seat is arranged in a valve cavity of the valve body. A valve deck is fixedly installed at the valve rod mounting port. The valve rod penetrates through a valve rod hole in the valve deck. The lower end of the valve rod is connected with a valve clack which forms a shutoff valve sealing pair with the valve seat. A control base is arranged above the valve deck. A first supporting piece and a second supporting piece which are fixed are arranged in a shell of the control base. The first supporting piece is provided with a vertical through hole serving as a supporting piece valve rod hole, and the valve rod penetrates through the supporting piece valve rod hole. A shutoff button is installed on the top of the valve rod. A startup button is connected to the second supporting piece in a sliding mode in the vertical direction. According to the instantly shutoff valve, a traditional operation mode of rotating a hand wheel or a handle is changed into button operation in the linear direction, duration for operation is shortened under the situation that the valve rod moves by the same distance, operation is convenient, and the instant switchover function can be achieved.