The invention provides air sand and a preparation method thereof. Air clay is prepared from the components of: silicon dioxide, calcined shell powder, polyethylene glycol, polyvinyl alcohol, foam powder k12, glycerol and propylene glycol. The preparation method comprises the following steps of: (1) adding the silicon dioxide which is used as a main body, the calcined shell powder which is used as a molecular structure connecting carrier, and the polyethylene glycol, the polyvinyl alcohol and the foam powder k12 which are used as reaction elements into a heatable reaction kettle; (2) stirring when the reaction kettle rotates at a constant speed of 25rpm; (3) raising the temperature to ensure that the reaction elements fully react with the silicon dioxide and the calcined shell powder to achieve an effect of shaping micro-particles; (4) after the temperature is up to 120 DEG C, stopping heating and continuously mixing; (5) adding a propylene glycol solution with the concentration being about 70 percent, stirring, mixing, and adjusting the rotating speed of the reaction kettle to be 20 rpm; (6) lowering the temperature, adding the glycerol, and adjusting the rotating speed of the reaction kettle to be 40rpm; (7) rotating for 10 minutes to obtain the air sand. The method has the characteristics of reasonable technological process and high product yield.