The invention discloses a continuous casting tundish, a crystallizer molten steel flow control device and a using method. The device comprises an electromagnetic stirrer, a cooling jacket and a heat insulating layer, wherein the electromagnetic stirrer is arranged on the outer side of an upper water opening and is located in a permanent layer below a working layer of the tundish, the cooling jacket is wrapped outside the electromagnetic stirrer and the heat insulating layer is wrapped outside the cooling jacket. An air inlet and an air outlet are formed in the cooling jacket and are used for leading cooling gas to cool the electromagnetic stirrer. According to the casting tundish and crystallizer molten steel flow control device, a rotating magnetic field is generated in the upper water opening, and the rotating magnetic field interacts with the molten steel passing through the upper water opening to generate electromagnetic force, the generated electromagnetic force enables the molten steel passing through the upper water opening to rotate and move so as to drive the molten steel near the upper water opening in the tundish to move, so that the effect of controlling the molten steel in the tundish to move is achieved. The continuous casting tundish and crystallizer molten steel flow control device achieves simultaneous control of flow of the molten steel in the continuous casting tundish and a crystallizer and achieves low liquid level pouring of the tundish. The continuous casting tundish and crystallizer molten steel flow control device and the using method are convenient and flexible to operate and strong in adaptability, improve continuous casting billet quality and the metal yield, and reduce the production cost.