The present disclosure provides a plant-based cat litter and a preparation method thereof, and relates to the technical field of pet products. In the present disclosure, the plant-based cat litter is prepared by coconut shell fiber, coffee grounds, starch, a binder, and water. The plant-based cat litter adopts purely natural, pollution-free, safe, and non-toxic raw materials, is easy to clean, has desirable adsorption and deodorization effects, and cannot be moldy after long-term storage. The plant-based cat litter is easy to use, is not easy to be broken and fractured during storage and transportation, and shows excellent coating properties on feces. Therefore, the plant-based cat litter can effectively improve a living environment of cats.