The invention provides a method for producing marsh gas by two-phase dry-type mixed anaerobic fermentation, belonging to the technical field of renewable energy sources. The method mainly comprises the following steps: ethanol prefermentation: inoculating a certain amount of dried yeast into kitchen waste to carry out ethanol prefermentation; and methane fermentation: mixing the kitchen waste subjected to ethanol prefermentation and vinasse in a ratio of 1:1 (on the basis of VS) as a substrate for subsequent anaerobic fermentation, and inoculating long-term acclimatized sludge in a ratio of 1:1 (sludge:substrate (on the basis of VS)). The method searches the possibility of optimizing methane anaerobic fermentation by ethanol prefermentation, and optimizes the experimental conditions for ethanol prefermentation. The method can effectively relieve the problem of volatile acid inhibition in the anaerobic digestion process, and obviously enhances the methane yield, thereby enhancing the energy recovery rate. The method is simple to operate, and thus, has high practical value.