In this study, a two-phase anaerobic digestion system was established to combine the bioenergy recovery and chemical oxygen demand (COD) removal. The synthetic brown sugar wastewater was used as a substrate. Six system organic loading rates (OLRs) from 12 to 32 kg/(m³·d) were analyzed. Results showed that the highest CH4 production rate (18.5 L/d) were obtained at OLR= 24 kg/(m³·d). The total energy recovery rate was calculated to assess the overall efficiency of energy recovery capacity. The highest energy recovery rate was 728.67 kJ/d, occurred at OLR=24 kg/ (m³·d). Meanwhile, the total COD removal was very high, up to 69.4%. Therefore, the system had a great contribution to energy recovery from brown sugar wastewater.