Abstract: Ageratina adenophora, the most harmful invasive plant in China, is toxic to animals, plants, and microbes. This paper describes work to develop a technique for composting A. adenophora in situ and evaluation of the decomposition effect to provide information on the effective elimination and resource utilization of this harmful plant. This study investigated the composting of Ageratina adenophora using incubation with Pseudomonas putita, Clostridium thermocellum, addition of urea and CaSO₄, and covering the stack with plastic film. Biological toxicity was evaluated at the end of bio-composting. The high temperature period (50.0-64.5 ℃) lasted for 22 days and detection of toxin in petroleum ether extracts decreased from 3.15 g/kg to 0.37 g/kg. After 80 days of bio-composting, and A. adenophora plant material was well decomposed. The compost contained 8.42% humic acids. The pH, organic matter and heavy metal concentrations of the compost matched the NY/525-2011 state standard. No effects on growth in wheat were detected following gavage of A. adenophora compost extract (ACE) with a large amount of water. Similarly, no pathologic changes in the main organs (heart, liver, kidney and lungs, mice) were detected either. Wheat seed germination, seedling vigor index and seedling height were increased by 8.65%, 28.79% and 23.69%, respectively compared with control (water soaked) seeds, when seeds were soaked seeds with ACE. In an incubation experiment, addition of bio-compost into soil increased microbial biomass carbon and nitrogen, and dehydrogenase activity compared with with untreated soil used as a control or soil which had received a chemical fertilizer treatment. This indicates that ACE promoted microbial growth, reproduction, and activity of soil. In summary, bio-composting successfully decomposed and detoxified A. adenophora herbage, and was able to produce organic fertilizer for agriculture, thereby effectively and economically eliminating and utilizing this invasive plant.