The nanoparticles of the hydrophobic drug of danazol with narrow size distribution are facilely prepared by controlled high-gravity anti-solvent precipitation (HGAP) process. Intensified micromixing and uniform nucleation environment are created by the high-gravity equipment (rotating packed bed) in carrying out the anti-solvent precipitation process to produce nanoparticles. The average particle size decreases from 55 mu m of the raw danazol to 190 nm of the nanoparticles. The Brunauer-Emmett-Teller (BET) surface area sharply increases from 0.66 m(2).g(-1) 15.08 m(2).g(-1). Accordingly, the dissolution rate is greatly improved. The molecular state, chemical composition, and crystal form of the danazol nanoparticles remains unchanged after processing according to Fourier transform infrared (FTIR) and X-ray diffraction (XRD). The high recovery ratio and continuous production capacity are highly appreciated in industry. Therefore, the HGAP method might offer a general and facile platform for mass production of hydrophobic pharmaceutical danazol particles in nanometer range.