Humidification device and air treatment system

The utility model provides a humidifying device which comprises a shell, a humidifying element, a water tank, a drainage disc and a drainage valve, the humidifying element, the water tank, the drainage disc and the drainage valve are arranged in the shell, the humidifying element and the water tank are arranged above the drainage disc, and the drainage valve is communicated with at least one of the water tank and the humidifying element and used for draining water in the water tank or the humidifying element to the drainage disc. A water outlet is formed in the side wall of the drainage disc, and a drainage port of the drainage valve is obliquely arranged downwards towards the water outlet of the drainage disc. According to the humidifying device, the water drainage opening of the water drainage valve is obliquely and downwards arranged towards the water outlet of the water drainage disc, residual water in the humidifying element and the water tank can be rapidly drained, and meanwhile water accumulation of t