Method for preparing biogas through co-fermentation of energy grass and macroalgae

The invention discloses a method for preparing biogas through co-fermentation of energy grass and macroalgae. The method comprises the following five steps: raw material pretreatment, primary fermentation at normal temperature, starting fermentation, stable aerogenesis and ending fermentation. The growth environments of energy grass and macroalgae are different, and the compositions of the energy grass obviously differs from and mutually complement that of the macroalgae, so that the gas generation rates of two raw materials are greatly improved, and the method has remarkable actual application value.