ObjectiveTo prepare crosslinked microspheres of chitin/alginate particles and characterize the microstructure and morphology. MethodsThe crosslinked microspheres of chitosan and sodium alginate mixture were prepared. The microstructure and morphology were detected by using infrared spectroscopy（FTIR）and scanning electron microscopy（SEM）. The drug slowly delivery property was studied with bovine serum albumin（BSA）as a drug model. Results It was showed that the chitin/alginate was well mixed and the crosslinked microspheres were formed under Ca2+ solvent. The encapsulation efficiency and release properties of the crosslinked microspheres were improved in comparison to the alginate microspheres, which being from 42% to 74% and drug release delayed from 4 h to 24 h. ConclusionThe chitin/alginate microspheres show pH responsive drug delivery properties, which release slowly under pH 1.2, and quickly under pH 7.0～7.4, and can be used in the colontargeted, drug delayed delivery system.