Abstract: The highly dispersed superfine silica powder with good shape，uniform particle size distribution，and pore size of 2~ 20 nm was prepared by parallel feed-in chemical method with sodium silicate（Na2O·3.27SiO2） and sulfuric acid as raw materials.The basic performance of SiO2 powder had been characterized by means of oil absorption value，BET，SEM，FT-IR， and XRD.The effects of several technical factors，such as the adding speed，surfactants，and detergents，on the silica powder were studied.The results showed that the optimum reaction conditions were as follows：adding speed of Na2O·3.27SiO2 was 70 r/min，no surfactant was added，ethanol was used as the detergent，drying at 85 ℃ for 2 h，and then went on drying at 100 ℃ for 2 h.Under those conditions silica particles were round or oval，in good shape and uniformly distributed.The surface area was 222.7 m2/g and the average pore size was 16.95 nm.

Key words: silica, parallel feed-in method, surfactant, detergent