A range hood, comprising: a hood housing, provided with a hood circulating air outlet and a hood exhaust outlet; a volute, having at least a portion disposed in the hood housing, defining a volute air passage therein, provided with a volute air inlet and a volute exhaust outlet that is in communication with the hood exhaust outlet, and comprising a fixed housing part and a movable housing part, the movable housing part being movable between a closed position and an open position relative to the fixed housing part, wherein when the movable housing part is in the closed position, the fixed housing part is fitted with the movable housing part and air in the volute air passage is allowed to be discharged from the volute exhaust outlet; characterized in that, when the movable housing part is in the open position, the movable housing part is staggered relative to a fixed side wall part of the fixed housing part to define a volute circulating air outlet in communication with the hood circulating air outlet between the movable housing part and the fixed housing part, so as to allow the air in the volute air passage to be discharged into a room through the volute circulating air outlet and the hood circulating air outlet sequentially, wherein when the movable housing part is in the open position, the movable housing part is not in contact with the fixed side wall part and located inside the volute air passage; wherein the movable housing part is reset from the open position to the closed position under an action of air pressure in the volute air passage; wherein the range hood further comprising: a fan wheel; a first limiting device disposed to the fixed housing part and located between the fan wheel and the movable housing part, wherein the first limiting device is provided for isolating the movable housing part from the fan wheel and ensuring a minimum distance between the movable housing part and the fan wheel; a second limiting device disposed to the fixed housing part and located outside the movable housing part and outside the volute air passage, wherein the second limiting device is provided for stopping an outer surface of the movable housing part when the movable housing part is in the closed position; a switching drive device configured to drive the movable housing part to move towards the open position. a hood housing, provided with a hood circulating air outlet and a hood exhaust outlet; a volute, having at least a portion disposed in the hood housing, defining a volute air passage therein, provided with a volute air inlet and a volute exhaust outlet that is in communication with the hood exhaust outlet, and comprising a fixed housing part and a movable housing part, the movable housing part being movable between a closed position and an open position relative to the fixed housing part, wherein when the movable housing part is in the closed position, the fixed housing part is fitted with the movable housing part and air in the volute air passage is allowed to be discharged from the volute exhaust outlet; characterized in that, when the movable housing part is in the open position, the movable housing part is staggered relative to a fixed side wall part of the fixed housing part to define a volute circulating air outlet in communication with the hood circulating air outlet between the movable housing part and the fixed housing part, so as to allow the air in the volute air passage to be discharged into a room through the volute circulating air outlet and the hood circulating air outlet sequentially, wherein when the movable housing part is in the open position, the movable housing part is not in contact with the fixed side wall part and located inside the volute air passage; wherein the movable housing part is reset from the open position to the closed position under an action of air pressure in the volute air passage; wherein the range hood further comprising: a fan wheel; a first limiting device disposed to the fixed housing part and located between the fan wheel and the movable housing part, wherein the first limiting device is provided for isolating the movable housing part from the fan wheel and ensuring a minimum distance between the movable housing part and the fan wheel; a second limiting device disposed to the fixed housing part and located outside the movable housing part and outside the volute air passage, wherein the second limiting device is provided for stopping an outer surface of the movable housing part when the movable housing part is in the closed position; a switching drive device configured to drive the movable housing part to move towards the open position. a fan wheel; a first limiting device disposed to the fixed housing part and located between the fan wheel and the movable housing part, wherein the first limiting device is provided for isolating the movable housing part from the fan wheel and ensuring a minimum distance between the movable housing part and the fan wheel; a second limiting device disposed to the fixed housing part and located outside the movable housing part and outside the volute air passage, wherein the second limiting device is provided for stopping an outer surface of the movable housing part when the movable housing part is in the closed position; a switching drive device configured to drive the movable housing part to move towards the open position.