The invention relates to the technical field of air conditioning and discloses a novel automatic air composition conditioning device and a control method thereof. The novel automatic air composition conditioning device comprises an air supplementing device, a pressurizing device, a washing device, an adsorption device, an ultrasonic wave atomizing device, an ultraviolet light sterilization device and an air-conditioning constant-temperature device which are arranged sequentially and are communicated mutually. The adsorption device comprises at least two adsorption tanks, activated carbon, kiselgel A, molecular sieves, a first program control valve blank, a second program control valve blank, a third program control valve blank and a fourth program control valve blank, wherein the lower portions, the middle portions and the upper portions of the adsorption tanks are filled with the activated carbon, the kiselgel A and the molecular sieves respectively, the first program control valve blank is communicated with the upper portions of the adsorption tanks, and the second program control valve blank, the third program control valve blank and the fourth program control valve blank are communicated with the lower portions of the adsorption tanks. The novel automatic air composition conditioning device and the control method thereof have the advantage that indexes such as temperature, humidity, impurity (for example, PM2.5) concentration, harmful component (for example, formaldehyde) concentration, oxygen content, CO2 content, ventilation volume and ventilation frequency can be conditioned automatically and continuously.