The invention discloses a preparation method of Yunkang capsules. 22 traditional Chinese medicinal materials such as Chinese yams, himalayan teasel roots and milkvetch roots are processed as follows: Step 1, the bulk drugs are soaked with warm water at the temperature of 50-60 DEG C and then filtered, and a filtrate is reserved for use; Step 2, dregs filtered out in Step 1 are decocted with water and then filtered, and a filtrate is reserved for use; Step 3, the filtrate obtained in Step1 and the filtrate obtained in Step 2 are merged, a bulk drug, namely, ass hide glue, is added, and the mixture is concentrated to be prepared into thick paste; Step 4, alcohol precipitation is performed on the thick paste obtained in Step 3, a supernate is taken and concentrated to be prepared into refined thick paste; Step 5, the refined thick paste obtained in Step 4 is depressurized and dried to be prepared into dry paste powder; Step 6, magnesium stearate and starch slurry are added into the dry paste powder obtained in Step 5, the magnesium stearate, the starch slurry and the dry paste powder are mixed evenly, and the capsules are obtained through filling. The preparation method of the Yunkang capsules can ensure that new dosage forms can realize effects of original Yunkang syrup and can satisfy actual production requirements and consumption needs.