The invention discloses a long-acting moldproof low-hygroscopicity high-adsorptivity plant fiber material type glass moldproof parting powder. The invention is characterized in that the parting powder is prepared by performing surface modification on a plant fiber powder. The preparation method comprises the following steps: adding plant fiber powder into a modifier solution, standing at 60-250 DEG C under the absolute pressure of 100-300 KPa to perform primary modification treatment, carrying out primary drying, adding an assistant or assistant solution to perform secondary modification treatment, and finally, carrying out secondary drying, wherein the modifier is selected from one or more of organic acids and acid salts, and the assistant is selected from one or more of silane coupling agents. The product has the characteristics of high adsorptivity and low hygroscopicity, has slowly released moldproof components, and is especially suitable for long-term storage or glass moldproofing in a transportation process under severe environmental conditions. The product is easy to clean, and can not influence the subsequent processing and use of the glass.