<p>To promote agricultural waste resource utilization and carbon neutrality goals, this study adopted the Life Cycle Assessment (LCA) method to construct a full-chain evaluation model covering “bagasse collection, pyrolysis carbonization, adsorption, soil disposal”, quantitatively analyzing the resource consumption and environmental impacts of each stage. The results indicate that the biochar obtained from processing 1 ton of bagasse achieves a net greenhouse gas emission reduction of 1.2 × 10³ kg CO₂-eq, demonstrating significant carbon-negative potential. Sensitivity analysis indicates that soil carbon sequestration and by-product energy substitution are the main drivers of emission reduction, while Monte Carlo simulation analysis further verified the robustness of the results. Furthermore, the system can effectively reduce acidification potential (–1.5 × 10⁻¹ kg SO₂-eq) and human toxicity potential (–3.95 × 10² kg 1,4-DCB-eq); however, attention must be paid to its negative impacts on photochemical ozone formation (8.2 × 10⁻¹ kg C₂H₄-eq), abiotic resource consumption (1.73 × 10⁻⁴ kg Sb-eq), and eutrophication potential (6.00 × 10⁻² kg PO₄³⁻-eq). The study demonstrates that bagasse-derived biochar production yields net positive environmental benefits, primarily driven by its carbon-negative effect, while also identifying specific impact categories requiring further optimization, thereby providing a scientific basis for advancing sustainable biomass utilization strategies.</p>