To comprehensively assess the lethality, uptake, depuration, accumulation and the effects of waterborne arsenic in freshwater fish, acute and chronic toxicities of As to Lanzhou catfish (Silurus lanzhouensis) were determined in present study.Our results demonstrated that 96-hour LC50 and safe concentrations (SC) for Lanzhou catfish exposed to arsenic are 12.88mg L-1 and 1.288mg L-1, respectively, four different arsenic concentrations of 0 mg L-1(C), 1.288 mg L-1 (T1), 0.5 mg L-1 (T2) and 0.1 mg L-1 (T3) were set in accordance with the logarithmic interval under SC to conduct the chronic exposure and recovery experiments.As accumulated in the target organs in the following order of concentration: gill > muscle > brain > liver, which is in accord with the variation of k1, the value of BCF and CAmax, k1 and CAmax declined with the decreasing.of arsenic concentration in different target organs, but BCF shows the reverse result.