This paper reviewed our group work on the high gravity (Higee) technology and its applications to nanoparticles production, which is fulfilled in a rotating packed bed (RPB). Fundamentals of the fluid now, mass transfer and micromixing in the RPB are discussed. Various pharmaceutical nanoparticles were prepared via reactive precipitation or anti-solvent precipitation in the RPB reactor. CaCO3 nanoparticles dispersion in overbased petroleum calcium sulfonate was produced by in situ synthesis of amorphous nano CaCO3 in microemulsions formed by neutral petroleum calcium sulfonate and CH3OH in the RPB. Commercial production of CaCO3 nanoparticles by the Higee technology has reached a throughput capacity of 36,000 t/y and a typical production line is illustrated and analyzed. As one example of the application of such commercially produced inorganic nanoparticles, polymer-based nanocomposites were produced by adding CaCO3 nanoparticles into different polymer matrixes such as PVC, ABS, PP, etc., and it was observed that nano CaCO3 significantly improved the mechanical properties of the polymer matrixes.