The invention relates to a preparation method for extracting an effective part from traditional Chinese medicine radix bupleuri and an application of the effective part obtained by utilizing the method and a preparation thereof in medicines for preventing and treating liver fibrosis, hepatocirrhosis, chronic hepatitis and the like. The preparation of the effective part of the radix bupleuri can be granules, soft capsules, capsules, dripping pills, tablets, dispersing tablets, effervescence tablets, injection and the like. The invention has simple operation method and utilizes a modern medicine effect sieving technology, an extracting and purifying technology, a preparation technology and a quality control technology to carry out deep development on the radix bupleuri preparation; the effective part of the radix bupleuri and the preparation thereof obtained by utilizing the technological method of the invention are rich in active components, have definite effective components, obvious pharmacological action, obviously enhanced medicine effect, stable performance, controllable quality, safety, reliability and small dose and are beneficial to the transportation and storage of the medicine and the taking of a patient.