Abstract: An air treatment device and a control method are provided. The air treatment device includes a water tank assembly, a water trough and a sterilization device. The sterilization device includes a sterilization portion, the sterilization portion is provided in the water trough, a water replenishing switch is provided between the water tank assembly and the water trough, and the water replenishing switch is configured to control connection and disconnection between the water tank assembly and the water trough. The air treatment device further includes a control portion, and the control portion is capable of controlling an opening and closing of the sterilization portion according to an on-off state of the water replenishing switch to ensure a good sterilization effect.