The invention discloses a preparation method of composite air purificant, comprising of an ore dressing step, a purifying step, a mixing step, a modification step, a granulation step, a roasting step and a finished product detecting and packing step, wherein in the ore dressing step, at least four purely natural mineral material ore concentrates with adsorbing ability are selected; in the purifying step, the selected mineral materials are purified; in the mixing step, the purified mineral material and proper caking agent are mixed properly according to weight ratio; in the modification step, modifying agent and vesicant are added, semi-drying modification is performed by adopting a kneader and drying is carried out in normal temperature; in the granulation step, a granulating machine is adopted for granulating, and active hole slash is carried out by controlling the temperature to 50 DEG C to 80 DEG C; in the roasting step, roasting activation is carried out by controlling the temperature to 200 DEG C to 300 DEG C; and in the finished product detecting and packing step, through screen separation, proper adsorption indicator allochroic silicagel particles are added, and the finished product is detected and packed to obtain composite purificant. The invention has the advantage that the performance of the product is excellent, the technology is energy-saving and environmental-friendly and can be repeatedly used; a user can intuitively judge that when regeneration is needed, the manufacture cost is low, and the like.