In order to enhance the harmless and resourceful utilization of human feces, this study utilized human feces as anaerobic fermentation substrate and pig manure fermentation liquid as inoculum. The effects of biochar derived from maize straw, wheat straw, and rice straw, added at proportions of 5%, 10% and 20%, were investigated on methane content and cumulative gas production during anaerobic fermentation. The results indicated that under constant temperature conditions of 35℃ for a fermentation period of 40 days, the highest cumulative gas production was observed in the group with 10% rice straw biochar (C₂), followed by the group with 10% wheat straw biochar (B₂), and the group with 20% maize straw biochar (A₃), with respective values of 6346, 5044, 4621 mL, respectivly. Both the control and treatment groups exhibited over 99% inactivation of fecal Escherichia coli and mortality of helminth eggs, achieving the objective of harmless treatment. In the anaerobic fermentation system of the biochar-treated groups, advantageous bacterial phyla, Proteobacteria and Synergistetes were detected, indicating a positive impact of biochar on anaerobic methane production from human feces.