Mass production of nanoparticles at low cost has attracted much attention from industrial and academic circles. In this paper, a novel method, the high gravity reactive precipitation (HGRP) technology, of manufacturing CaCO3 nanoparticles, presently scaled-up to an annual capacity of 10,000 tons, is presented. This paper describes the process principle, the process design and experiments on the syntheses of 15-30 nm CaCO3, 30-50 nm SiO2,20-30 nm TiO2, 20-60 nm ZnO, 20-30 nm ZnS, 30 nm SrCO3, 40-70 nm BaTiO3, stick-like nano BaCO3 as well as nano-fibrillar aluminum hydroxide measuring 1-10 nm in diameter and 50-300 nm in length, using liquid-liquid,gas-liquid and gas-liquid-solid reactant systems. The advantage of using the HGRP technology is illustrated by comparison to conventional methods.