A plant microbial fuel cell includes a planting container, a plant, a cathode and an anode. The planting container has a culture medium therein, and a microbial population is in the culture medium. The plant is grown in the culture medium in the planting container. The cathode is disposed on a surface of the culture medium, and the anode is arranged in the culture medium close to roots of the plant. The anode includes a porous carbon material prepared from coffee grounds, and thus the overall cost of the plant microbial fuel cell can be greatly reduced, and the porous carbon material is easy to process and has high biocompatibility. |