The objective of this study was to investigate the impact of six kinds of biochar on anaerobic digestion (AD) for kitchen waste. The utilized types were agricultural waste biochar (BC-AW) and sewage sludge biochar (BC-S) chemically activated in acid (H₃PO₄) and base (KOH). The results indicated that all biochar products promoted the shortening of stasis, weakening acidification and accelerating organic matter degradation, as well as increasing the activity of methanogenic bacteria. Agro-wastes -derived biochar activated with base (BC-AW-KOH) had the greatest cumulative gas production (2250 mL/gVS and 72% methane yield), attributed to having the highest surface area (2111.9 m²/g) and an improved pore structure. Inactivated sludge biochar (BC-S) showed the least performance and productivity. The Transport Function model was also found to be the best statistical description of the experimental data, as revealed by kinetic modelling. According to these observations, treatment of biochar by chemical activation is a promising approach for improving the stability of the anaerobic digestion system and energy recovery from organic waste.