Abstract: Two-phase anaerobic fermentation has the advantages of high organic load and fermentative stability, low hydraulic retention time (HRT) and high biogas yield, compared with single-stage methane fermentation. In order to improve the rate of anaerobic fermentation of caw manure, two-phase fermentation was researched at (35±2)℃, which fermentative solution was from mixture of dairy manure and water by solid-liquid separation. Results showed that COD removal rate and biogas yield of substrates’ volatility solid content reached about 52.81% and 181.45 L/kg under the conditions of 3 d HRT of acidogenic phase and 7 d HRT of methanogenic with 1 d fermentation, which fermentation material was 5 L and TS concentration was 6.60%. The results can provide references for reclamation of dairy manure.