According to the guideline of OECD 235 and 218, the toxicity of phenanthrene (Phe) to Chironomus riparius larvae was studied. In the toxicity experiments, survival rate and emergence time were used as endpoints. The acute toxicity (48 h) was assessed by using spiked water and the chronic toxicity (28 d) was assessed by using spiked sediments. The results showed that for acute toxicity, the 24 h and 48 h lethal concentrations to 50% of organisms (LC50) of Phe in water to C. ripurius larvae were 1100 and 337.2  μg·L^-1, respectively. For chronic toxicity, the 28 dLC50 of Phe in sediment and in pore water to C. ripurius were 24.9 mg·kg^-1 and 10.4  μg·L^-1, respectively. Additionally, the mean emergence time of the larvae was advanced with the increasing concentration of Phe in sediments. When the concentration of Phe in sediments increased to 5 mg·kg^-1, the average emergence time of test organisms was significantly earlier than control and lowexposure concentration groups (P<0.05). When the exposed concentration in sediments increased to 10 mg·kg^-1, the average emergence time was 3.8 d shorter than control group, and from 5 mg·kg^-1 on, the average emergence time of different exposure concentrations was similar to each other (3.7-4.2 d).