The invention provides a method for preparing multi-variety boron carbide micro-powder. The method comprises the following steps: conducting primary or secondary grinding on a boron carbide material, and conducting classifying, drying and screening steps to prepare multiple varieties of boron carbide micro-powder with different granularities. In the method, a heterogeneous medium is not introduced in the grinding process, generation of massive impurities in production by a conventional ball-mill method can be avoided, and a pickling or rinsing process in the later period is not required, so that massive water resource and energy consumption can be saved, production cost can be reduced, environmental pollution is avoided, and environmental protection is benefited; and a two-stage grinding mode is adopted, so that the phenomena of over-ground raw material and big granularity width in a conventional ball-mill method can be avoided, and the product yield can be improved. Furthermore, the method is simple in flow, short in production cycle and high in production efficiency, so that the production cost can be remarkably reduced. The method has the advantages of simple and feasible process, short production cycle, high product yield, low processing cost, environmental friendliness, water resource saving and the like.