To evaluate the bioavailability of ellagic acid loaded super-saturatable self-microemulsifying drug delivery system (S-SMEDDS), its pharmacokinetic properties were studied in rats with an ultra-high performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry. The plasma samples were treated by solid-phase extraction method, and gallic acid was used as the internal standard when determining the concentration of ellagic acid. Results showed that the established analytical method was sensitive and accurate, which is applicable to the pharmacokinetic study of ellagic acid. The drug was found to be absorbed rapidly