Abstract: CsA-loaded N-octyl-O-sulfate chitosan （NOSC） micelles containing Carbopol 940 (CsA-M-C) were prepared by dialysis-mixed method as a topical ocular nano-formulation for the treatment of dry eye syndrome.CsA-M-C was characterized by dynamic light scattering (DLS) assay and transmission electron microscope (TEM),respectively.The particle size of CsA-M-C was （193.4±1.56） nm with an acceptable dispersity.Furthermore,the pharmacokinetics and pharmacodynamics of CsA were evaluated after topical ocular administration of CsA-M-C,CsA-loaded NOSC micelles without Carbopol 940 (CsA-M) and CsA castor oil preparation (CsA-oil) in rabbits.AUC of CsA-M-C was 6.6- fold and 3.9-fold of CsA-M and CsA-oil.And MRT of CsA-M-C was 1.6-fold and 7.5-fold of CsA-M and CsA-oil,respectively.Additionally,there was a significant difference in breaking-up time between CsA-M-C and CsA-oil group (P<0.05).In conclusion,CsA-M-C presents a potential promise in future therapy for dry eye syndrome.