The invention discloses a preparation method of soymilk. The preparation method comprises the following steps: (1) soybean treatment; (2) soybean milk extraction; (3) soybean milk emulsification; (4) slurry emulsification; (5) blending; (6) homogenization; (7) secondary homogenization; (8) storage; (9) bottle disinfection; (10) filling; (11) caging and sterilization; and (12) packaging and putting into storage. In a preparation process, high quality non-transgenic soybeans are selected. By adopting advanced processes of advanced superhigh temperature deodorization, astringency removal, high-pressure homogenization and UHT sterilization, the soymilk is more fragrant in taste and mellower and can be drunk all the year round. According to the preparation method of soymilk disclosed by the invention, the quality of a finish product soymilk can be kept stable within a relatively long time by two times of operations of homogenization and sterilization, so that the soymilk is of storage tolerance.