Abstract: The specific biogas yield of two-phase anaerobic digestion of water hyacinth and animal excrete is 330 L/kg-fresh water hyacinth with methane content about 75%, and the yield is about 3.4 times that of direct two-phase anaerobic digestion. Effluent CODCr and SS are less than 235 mg/L and 40 mg/L, respectively. During the stable running course of system, its acidification phase is in a acetification condition. The start time of this process is short, which effectively overcomes some drawbacks existed in the running course of current methane-generating pit, such as floating sludge and sludge conglomeration; this process also increases the biogas yield and keeps the stable running of system, therefore this process is very practical.