The invention relates to a method for controlling Pichia pastoris to ferment to produce an antibacterial peptide by utilizing dissolved oxygen parameters, and belongs to the technical field of biological engineering. The method comprises the following steps of: (1) calibrating the percent of dissolved oxygen (DO) to obtain a fermentation medium; (2) simultaneously marking the percent as a 0 pointand starting to ferment; (3) when the value of the DO is up to above 50 percent from 10 percent below, starting to feed methanol until the value of the DO falls back to 10 to 30 percent; stopping feeding the methanol; when the value of the DO is stably up to over 50 percent again, starting to feed the methanol again until the value of the DO falls back to 10 to 30 percent; stopping feeding the methanol; operating circularly; and controlling the value of the DO to be maintained between 10 and 30 percent all the time by feeding the methanol, adjusting ventilation and controlling a rotation speed; and (4) when the value of the DO does not fall back after feeding the methanol, finishing fermenting. The method of the invention has a short fermentation period and less dosage of the methanol; and compared with conventional dissolved oxygen value regulation and control, the method is easier to operate, and conditions are easier to grasp.