The invention discloses an irbesartan hydrochlorothiazide capsule and a preparation method thereof, belonging to the technical field of medicines. In the preparation method, the kinds and the dosages of a bulking agent, a disintegrating agent, an adhesion agent and a glidant are screened, and process conditions that raw auxiliary materials are screened by a specific sieving mesh number, hydrochlorothiazide is uniformly mixed by using an equivalent gradual increase method, grains are fluidized and dried, and the like are adopted in the preparation process, thus the prepared capsule has good dissolution, small loading quantity difference, high stability and bioavailability, good curative effect and good patient compliance because the capsule can conceal the bitter taste of the medicines; and besides, the invention has few auxiliary material kinds in a prescription, simple production process and low cost.