The invention discloses a method for preparing a bamboo charcoal-based lithium ion battery electrode material by utilizing a physical activation method. The method comprises the following steps: cleaning bamboos and then drying; placing the dried bamboo into a porcelain kettle, placing into a high-temperature furnace and charring under high temperature under argon protection, thereby acquiring bamboo charcoal; grinding the bamboo charcoal into powder and sieving, thereby acquiring the bamboo charcoal powder in uniform grain size; introducing the bamboo charcoal powder into carbon dioxide, activating under high temperature and naturally cooling, thereby acquiring an activated bamboo charcoal material; and respectively soaking the bamboo charcoal material by using deionized water and ethyl alcohol, thereby acquiring the bamboo charcoal-based lithium ion battery electrode material. The preparation method disclosed by the invention has the characteristics of simple and feasible operation, high repeatability, low cost and no pollution to environment. The bamboo charcoal material prepared according to the method is used as the lithium ion battery electrode material. The charring and cleaning physical activation preparation method is capable of effectively increasing the specific surface area of the material, so that the battery capacity can be further increased and the cycling performance can be enhanced.