The invention relates to the field of traditional Chinese medicine preparations, and in particular to a lentinan granule and a preparation method thereof. The granule consists of lentinan and an excipient, and the excipient is one or more of microcrystalline cellulose, modified starch, maltodextrin and aerosol. By adopting an appropriate type of excipient according to an appropriate proportion, in combination with suitable dry granulation conditions, the invention ultimately obtains the lentinan granule, the moisture absorption and flowability of the lentinan powder are effectively improved, moreover, yield and drug-loading capacity are significantly increased, the requirement of further preparation formation can be met, and the subsequent development of traditional Chinese medicine preparations is benefited. Moreover, equipment needed by the preparation method disclosed by the invention is simple, the period of production is short, the production cost is greatly reduced, the efficiency of production is increased, and the preparation method is suitable for use in mass production, and has a good application prospect.