[Objective] This study was aimed to study the pharmacokinetics of iver- mectin in Salvelinus leucomaenis following a single oral administration or intraperi- toneal injection. [Method] After a single oral administration or intraperitoneal injection of ivermectin with a dosage of 0.3 mg/kg body weight, samples were taken at dif- ferent time points and determined by high-performance liquid chromatography-ultravi- olet detection （HPLC-UV）. The pharmacokinetic parameters were calculated by 3p97 software. [Result] The concentration-time relations of ivermectin in plasma, muscle, liver and kidney were well described by one-department open model with first-order absorption. After oral administration, the pharmacokinetic parameters in plasma were as follows： Tmax=4.503 h, Cmax=0.252mg/L, t1/2ka=0.476 h, t1/2ka=331.160 h, AUC=121.524 （mg/L） .h. After intraperitoneal injection, the pharmacokinetic parameters in plasma were as follows： Tmax=2.751 h, Cmax=0.230 mg/L, t1/2ka=0.306 h, t1/2ka=153.868 h, AUC= 51.689 （mg/L） .h. [Conclusion] There were differences in the pharmacokinetics of ivermectin in Salvelinus leucomaenis between two different administration routes, and intraperitoneal injection led to more rapid absorption than oral administration.
