The growth of Tubificidae was investigated from juvenile to adult stage for 16 weeks by cultivating Tubificidae with activated sludge as substrate in batch tests at two different temperatures (20 degrees C and 25 degrees C), monitoring changes of body length and wet weight of Tubificidae. Results showed that the growth of Tubificidae well fit the Logistic curve. Temperature of 25 degrees C was more suitable for worm growth than of 20 degrees C with the growth rates of wet weight and body length of 0.0470 mg x (ind x d)(-1) and 0.1936 mm x (ind x d)(-1), respectively, at 25 degrees C. Meanwhile, the relationship between body length and wet weight of Tubificidae at 25 degrees C was determined as W = 0.008 L(2.028) (R2 = 0.868 5), which was well in accordance with the common regulation concluded in previous studies. Compared with other substrates, Tubificidae showed little difference on growth when fed with activated sludge.