For slurry recirculation can improve the performance of anaerobic digestion system while inadaptable recirculation rate may lead to acidification,an anaerobic digestion experiment was carried out on kitchen waste to analyze the effect of slurry recirculation.Results showed that the average daily biogas production was increased by 0.7%,13.0% and 4.9% than its non-recirculation period when the recirculation rate was 10%,30% and 50%,respectively.Slurry recirculation had no harm to the methane percentage.With an increased recirculation rate,system's buffer capacity reduction performed better,but high recirculation rate(50%) would lead to sodium ion accumulation.