The present invention relates to the field of medical chemistry, and discloses a preparing method for three crystal forms of cabazitaxel, that is, crystalline form J of cabazitaxel esterate, crystalline form G of cabazitaxel hydrate and crystalline form I of cabazitaxel, and a novel crystalline form of cabazitaxel. The novel crystalline form of cabazitaxel according to the invention has good stability and good solubility in commonly used solvents, and is easy to be preserved and is stable under treatment during preparation of dosage forms, thus could be used for the preparation of a medicament for treating prostate cancer.
