The invention discloses a microbial nucleic acid extraction method. The method comprises the following steps: a, preparation of a microbial liquid sample: firstly, adding a microorganism-containing sample into a culture dish filled with a nutrient solution, and shaking lightly and uniformly to obtain a liquid sample for later use; b, filtration of microorganisms: slowly pouring the liquid sample in the culture dish onto a filtering membrane in order that the microorganisms in the liquid sample adhere to the surface of the filtering membrane; c, transfer of the microorganisms: placing the filtering membrane into a solution, and cleaning the filtering membrane repeatedly in order to transfer the microorganisms on the surface of the filtering membrane into the solution; d, extraction of microbial nucleic acid: performing heating treatment on the solution at the temperature of 85-95 DEG C for 10-15 minutes in order that the microorganisms are dissolved, and nucleic acid is released into the solution. The microbial nucleic acid extraction method is easy to operate, and has a high extraction speed; the nucleic acid in the microorganisms can be effectively extracted for later use in research and development activities, so that early-stage guarantee is provided for the research of relevant characteristics of the microorganisms.