The present invention provides a non-solvated amorphous form of (2α,5β,7β,10β,13α)-4-acetoxy-13-({(2R,3S)-3[ (tert-butoxy carbonyl) amino]-2-hydroxy-3-phenylpropanoyl}oxy)-1-hydroxy-7,10-dimethoxy-9-oxo-5,20-epoxytax-11-en-2-yl benzoate or Cabazitaxel (I), and process for preparation thereof. The present application also provides a non-solvated amorphous form of (2α,5β,7β,10β,13α)-4-acetoxy-13-({(2R,3S)-3[ (tert-butoxy carbonyl) amino]-2-hydroxy-3-phenylpropanoyl}oxy)-1-hydroxy-7,10-dimethoxy-9-oxo-5,20-epoxytax-11-en-2-yl benzoate or Cabazitaxel (I) having an XRPD pattern as per FIG. 1, and IR spectrum as per FIG. 3 and is useful as an active pharmaceutical in a pharmaceutical composition comprising thereof and has anti-cancer activity.