The invention relates to the technical field of medical supplies, in particular to a method for preparing medical air-permeable tape. The method comprises the steps that pure cotton gauze is unwound from a fabric unwinding device and passes through an adhesive tank, a scraper and a cloth support roller, the front surface of the pure cotton gauze is coated with a solvent-type medical pressure-sensitive adhesive in the adhesive tank through scraping, the pure cotton gauze coated with the solvent-type medical pressure-sensitive adhesive enters an infrared oven for pre-drying, the infrared oven isinternally provided with a high-pressure air perforating device, high-pressure air is blown from the back surface of the pure cotton gauze, and before the solvent-type medical pressure-sensitive adhesive is completely dried, the medical pressure-sensitive adhesive on the front surface of the pure cotton gauze forms dense fine air-permeable holes by blowing the high-pressure air from the back surface of the pure cotton gauze.