OBJECTIVE： To study the effects of ritonavir on the pharmacokinetics of sufentanil in rabbits. METHODS： 24 rabbits were randomly divided into 2 groups， with 12 rabbits in each group. Trial group was given ritonavir 10 mg/kg by gavage and then injected sufentanil 2 μg/kg intravenously after 5 min. Control group was given equal volume of normal saline by gavage and then injected sufentanil 2 μg/kg intravenously. Arterial blood samples 0.3 ml were taken before gavage and 0， 0.25， 0.5， 1， 2， 3， 4， 6， 8， 10， 12， 14， 24 h after intravenous administration. The plasma concentrations of sufentanil were determined by LC-MS/MS， and DAS 2.0 software was adopted to calculate pharmacokinetic parameters. RESULTS： The pharmacokinetic change of sufentanil conformed to two-compartment model in 2 groups. The pharmacokinetic parameters of sufentanil in control group vs. trial group were that t1/2 were （22.0±6.59） and （26.4±1.41） h； MRT0-24 h were （8.6±2.08） and （12.1±3.70） h； AUC0-∞ were （16.1±5.17） and （38.1±12.95） mg·h/L， respectively. There was statistical significance in MRT0-24 h and AUC0-∞ between 2 groups （P＜0.05）. CONCLUSIONS： Ritonavir can elevate distribution of sufentanil in rabbits， and prolong retention time of sufentanil.