OBJECTIVE： To study the pharmacokinetics behaviors and the bioavailability of aspirin phospholipid complex self-microemulsion in rats in vivo. METHODS： 12 SD rats were randomly divided into aspirin suspension group （10 mg/kg） and aspirin phospholipid complex self-microemulsion group （10 mg/kg）， 6 in each group. Rats were intragastrically administrated， and blood sample 0.6 mL was taken from jugular vein before administration and after 0.083， 0.25， 0.5， 0.75， 1.0， 2.0， 3.0， 4.0， 6.0， 8.0， 12.0 h of administration. HPLC was used to determine the concentration of salicylic acid in rats’ plasma. DAS 2.0 pharmacokinetic software was adopted to calculate the pharmacokinetic parameters and relative bioavailability. RESULTS： The pharmacokinetic processes of both aspirin suspension and aspirin phospholipid complex self-microemulsion were in line with one-compartment model. The salicylic acid of cmax of rats in aspirin suspension group and aspirin phospholipid complex self-microemulsion group were （1.904±0.208）， （6.457±1.091） μg/mL； AUC0-12 h were （12.860±1.327）， （47.270±12.860） μg/（h·mL）； tmax were （2.167±0.983）， （0.917±0.540） h， respectively. Compared with aspirin suspension， salicylic acid of cmax and AUC0-12 h of aspirin phospholipid complex self-microemulsion in rats in vivo were significantly increased （P＜0.01）， while tmax was significantly decreased （P＜0.05）； the relative bioavailability was 367.57％. CONCLUSIONS： Making aspirin into phospholipid complex self-microemulsion can improve the gastrointestinal absorption， with high relative bioavailability.