The invention provides a preparation method of a mesoporous carbon material. The mesoporous carbon material is composed of amorphous carbon and has a concentratedly distributed mesoporous channel system; and the pore size is in a range of 7 to 9 nm. The carbon material is prepared by the following steps: at first, mixing calcium carbonate and ethanol, then adding distilled water, carbohydrates, and silica sol, evenly mixing, then carrying out an ultrasonic treatment, drying, carrying out a high temperature treatment in an atmosphere of nitrogen gas, finally reacting the material with an acid solution and an alkali solution, washing, and drying to obtain the carbon material. The provided preparation method has the advantages that no pricy organic additive is used, the operation is simple and easy to perform, and the production cost is low.