The invention discloses a preparation process and an application of calcium magnesium acetate. The preparation process comprises the following processing steps: preparing a calcium acetate solution, and performing press filtration, MVR concentration and centrifugal spray-drying. The preparation process disclosed by the invention is simple in technical process, easy to operate, easy in raw material acquisition, free from emission of three wastes in an overall production process, high in production efficiency, high in yield, low in equipment investment, wide in application and remarkable in economic benefits. The calcium magnesium acetate prepared by the process disclosed by the invention has the functions of melting snow, deicing, resisting dust, preventing dust and controlling atmospheric pollution; as a snow melting agent, the calcium magnesium acetate is higher in snow melting capability and enables accumulated snow and ice layers to be loose so that the snow and the ice layers can be removed more easily; as a dust resisting agent, the calcium magnesium acetate can be used for removing NOx and SO2 generated by combustion of coal and HCl generated by combustion of PVC (Polyvinyl Chloride) so as to control the atmospheric pollution; moreover, the calcium magnesium acetate causes quite low corrosion to metals and causes no toxic or side effects to human, soil and plants.