Abstract: AimTo investigate the formation mechanism, macromolecular drug loading capacity and release property of alginate-chitosan microcapsules (ACM). MethodsACM was prepared by emulsification-gelation method and its formation mechanism was studied by DSC analysis. Using bovine serum albumin (BSA) as model drug, the drug loading and release properties of the microcapsules on macromolecular drug were investigated. ResultsThe results of DSC analysis showed that there is electrostatic interaction between materials encapsulated in the microcapsule. With the increase of BSA microcapsule ratio, the BSA loading precentage rose from 9.20％ to 35.08％;and with the ascent of chitosan (CTS) concentration, the BSA loading percentage increased from 30.29％ to 38.12％. The BSA microcapsules whowed a two-phase release in both 0.1 mol·L^-1 HCl and phosphate buffer saline (pH 7.4). With the increase of CTS concentration, the BSA release more and more slowly in 0.1 mol·L^-1 HCl. ConclusionSpheric and well-dispersed alginate-chitosan microcapsules were prepared. The microcapsule showed good loading capacity to BSA as well as sustained release to a certain degree.