Abstract: AIMTo study the chemiluminescence mechanism of Tb(III)-RFX-Ce(IV)-Na₂SO₃ system and establish a new method for the determination of rufloxacin (RFX) in capsules and human urine samples. METHODS RFX was injected into Na₂SO₃ standard solution,then mixed with Tb³⁺, Ce⁴⁺ in turn, the chemiluminescence signal was detected by weak luminescence analyzer. RESULTSThe chemiluminescence intensity was linearly related to the concentration of RFX in the range of 2.0×10^-9～1.0×10^-6 mol·L^-1 with a detection limit of 3.8×10^-10 mol·L^-1. The familiar excipients such as starch and dextrine do not cause interference. So, this method can be applied to the determination of RFX in tablet. The content and recovery of RFX in urine can be directly detected without pretreatment. CONCLUSIONIt provides a simple, rapid, highly sensitive and highly selective method of rufloxacin for pharmacokinetic studies and clinical treatments.