Objective To establish the method of measuring quercetin content in semen cuscutae(SC) and to explore its in- vivo pharmacokinetics features.Methods The rapid and sensitive HPLC- UV method was adopted with carbamazepine acting as internal standard. After the extract of SC was given, serum samples of rats were collected and measured on C18 reverse- phase chromatographic column after liquid- liquid extract. Results The linear range of calibration curve were 0.05～ 9? g/mL (r=0.9998). The method showed good precision and recoveries for serum with 86.65～ 99.07% , and extracting recoveries 79.91～ 84.56% .The limit of detection(LOD) as 0.05? g/mL. Conclusion The pharmacokinetic process of quercetin in vivo manifestated an opening two- compartment model with t1/2(Ab)=0.13h, t1/2(? )=0.19h, t1/2(? ) =1.22h, tmax=0.333h. The results may provide evidence of safety and effectiveness for clinical use of SC.