The invention provides an oven and a humidifying assembly thereof. The humidifying assembly comprises a heating tube and a water box, the heating tube forms one or more parts of a baking heating device of the oven, the water box comprises a box body and a connecting part connected with the box body, the connecting part is used for being connected with an oven body of the oven, the box body limitsa water groove with an upward opening, the water groove is located below the heating tube, and heat generated by the heating tube generates steam. According to the humidifying assembly, the oven has the function of humidifying, so that the taste of foods is improved. In addition, the water groove is located below the heating tube, and therefore, during humidifying, water in the water groove only utilizes the heat below the heating tube; since the heating tube forms one or more parts of the baking heating device of the oven, cooperation of a heating tube and a water box of an existing oven is directly utilized, in this way, the function of humidifying can be realized, the structure of the oven is simplified remarkably, and then the production cost for the oven is lowered easily.