The invention relates to a drying agent and in particular relates to a preparation method of a charcoal particle drying agent. The preparation method of the charcoal particle drying agent comprises the following steps: uniformly mixing the raw materials; carrying out electronic radiation crosslinking treatment; and processing the raw materials into particles, strips or sheets. The raw materials comprise the following components in parts by weight: 60-80 parts of bamboo charcoal powder, 15-25 parts of bentonite, 10-13 parts of calcium chloride, 9-12 parts of magnesium sulfate, 5-8 parts of starch, 4-9 parts of attapulgite ore, 6-11 parts of hard gypsum ore, 1-3 parts of bamboo leaf oil, 3-7 parts of adhesive liquid, 0.1-0.5 part of capraldehyde, 0.2-0.4 part of linalool, 0.02-0.06 part of thymol, 0.6-0.9 part of glyceryl triabietate and 5-8 parts of a moisture absorption additive. The moisture absorption additive is selected from polyvinyl alcohol fiber, polyoxyethylene fiber, alginate fiber and mulberry silk; the adhesive liquid comprises phthalic anhydride, furfuryl alcohol, triethylene glycol, glutaric acid, butantriol, zinc oxide powder, magnesium oxide, chloroprene rubber, elastic rubber, softening oil, dimethyl carbonate, benzoyl peroxide, acetic ether, an emulgator, flour, nano-silver, a fire retardant, methylcellulose and deionized water. The drying agent is high in drying performance and fresh and natural in smell, and has a good deodorizing effect.