OBJECTIVE： To study relative bioavailability of dauricine self-microemulsifying drug delivery system （SMEDDS） in rats. METHODS： 12 rats were randomly divided into dauricine SMEDDS group （20 mg/kg） and dauricine solution group （50 mg/kg）， 6 rats in each group. They were given relevant medicine intragastrically. Then， 0.3 ml plasma was collected from orbital venous plexus before medication and 0.167， 0.333， 0.5， 0.75， 1， 2， 4， 8， 12， 24， 36 h after medication. The plasma concentration of da- uricine was determined by HPLC-MS/MS， and DAS 3.0 was used to calculate pharmacokinetic parameters and evaluate the relative bioavailability of dauricine with dauricine SMEDDS. RESULTS： The linear range of dauricine in plasma were 2.12-424 ng/ml （r＝0.999 9）； RSDs of intra-day and inter-day were all lower than 10％. Pharmacokinetic parameters of dauricine solution and dauricine SMEDDS were that cmax were （126.3±37.4） ng/ml and （179.6±51.5） ng/ml； t1/2 were（11.48±4.58） and （21.79±6.59） h； AUC0-t were  （1 963.5±638.3） ng·h/ml and （2 535.8±739.5） ng·h/ml； AUC0-∞ were （2 256.3±703.5） ng·h/ml and （2 854.6±768.7） ng·h/ml， respectively. The relative bioavailability of dauricine SMEDDS were 323％ and 316％ by calculating with AUC0-t and AUC0-∞， respectively. CONCLUSIONS： Intragastric administration of dauricine SMEDDS can improve relative bioavailability of dauricine significantly.