Toxic data of local fishes was very essential in the derivation of local water quality criteria. In this study, two local fishes (S.dabryi and P.parva) of Liao River were chosen to conduct 96-h acute toxic data under ammonia (total ammonia) whose pollution was proved to be serious in Liao River. 96 h LC50s of S.dabryi and P.parva under total ammonia were 35.36 mg/L (pH=7.50, T=20.00°C) and 30.35 mg/L (pH=7.50, T=20.00°C), respectively. These toxic values could be used to supply the local database which was the basement to formulate site-specific water quality criteria accordingly in Liao River.