The present invention provides a process for preparing amorphous Cabazitaxel from the solvate form of Cabazitaxel. The present invention also provides novel diisopropyl ether solvate form of Cabazitaxel (I), and process for preparation thereof. Said amorphous Cabazitaxel and crystalline diisopropyl ether solvate of Cabazitaxel of the present invention can be utilized in preparing the pharmaceutical composition/s useful in the treatment of cancer.