The invention discloses a high-density culture method for bacilli and a culture medium. The high-density culture method for bacilli comprises the following steps including Step 1, strain domestication, Step 2, shake flask seed culture, Step 3, seed tank seed culture, and Step 4, fermentation tank high-density fermentation culture. Ingredients of a fermentation culture basic culture medium comprise peptone, yeast powder soaking, glucose, disodium hydrogen phosphate, monopotassium phosphate, magnesium sulfate, manganese sulfate, calcium chloride and bean pulp. A fermentation culture medium supplemental culture medium is glucose solution, the glucose content in the glucose solution is 3 to 4 percent of the total quantity of the fermentation liquid, and the high-density culture method for bacilli is applicable to the high-density culture of bacillus subtilis and bacillus licheniformis. The high-density culture method for bacilli provided by the invention has the advantages that the spore forming rate of the bacilli in the fermentation liquid can be higher than 90 percent, and the spore density is higher than 120 hundred million / milliliter to the lowest degree.