Small aquatic Oligochaetes are the typical metazoa found frequently in the activated sludge and bio-film from wastewater treatment system. Effect of environmental factors on growth characteristics of aquatic Oligochaetes, Aeolosoma hemprichi, Pristina longiseta, Nais variabilis were investigated. Using a sterilized activated sludge as the metazoan food, the monoxenic growth rate of small aquatic Oligochaetes, the effects of temperature, pH, phosphate buffer solution concentration, shake stress, food concentration were measured. Optimum temperature of A.heyprichi, P.longiseta, N.variabilis were 30, 35, 35°C, respectively. Phosphate buffer concentration which could grow normally were 1/375M for A. hemprichi, 1/150M for P. longiseta and N.variabilis. The optimum pH values in cultivating the Oligochaetes ranged from 5 to 9. The endurance of A. hemprichi against shake stress was higher than that of P. longiseta and N.variabilis.