Abstract: Calcium alginate microspheres and calcium alginate/poly-L-histidine microcapsules were prepared by emulsification. The influences of different concentrations of sodium alginate and calcium chloride on the properties of microspheres，such as appearance，particle size，drug-loading amount and controlled-release properties were investigated. The results showed that particle size was mainly determined by the concentration of sodium alginate，the distribution of microspheres and their diameters were mainly affected by the concentration of calcium chloride. Drug-loading amount decreased with the increase of the concentration of sodium alginate and calcium chloride，but the burst release of microcapsules was not obvious.