Abstract: Aim ：To prepare novel cubosome system for effective ocular drug delivery with dexamethasone(DEX) as model drug，and investigate its pharmacokinetic profile in rabbit aqueous humor. Methods ：DEX cubosomes was prepared by the method of high-pressure homogenization，and its particle size was determined by the laser particle sizer，and the microstructure observed by cryo-TEM.In addition，Draize method was used to evaluate the ocular irritation of DEX cubosomes. Finally，aqueous humor microdialysis was utilized to evaluate its pharmacokinetics in rabbits. Results ：Average diameter of DEX cubosomes was about 200 nm，and the cubic structure of the particles was evident under the cryo-TEM.It was indicated by Draize scores that this dosage form exhibited excellent ocular tolerance.Results of pharmacokinetic profiles in aqueous humor showed that AUC _0→240 and c _max of the rabbit group administered with DEX cubosomes were significantly higher than those of the control group(DEX sodium phosphate eye drops)，with AUC_0→240 of the formulation F1(10% oil content) and F2(20% oil content) is being about 1.8 and 2.9 times higher than those of the control group，respectively(P<0.05). Conclusion ：The novel ocular drug delivery system of DEX cubosomes was capable of increasing significantly the drug concentration in aqueous humor，and improving the ocular bioavailability.