To avoid the reaction of calcium iodate with reducing substances such as vitamin c (VC) during storage and use in feeds. The microspheres of calcium iodate (Ca(IO3)2/SAMS) were prepared by improved emulsification/internal gelation with calcium iodate as core material, sodium alginate as wall material and Nano-calcium carbonate as cross linker. The Ca(IO3)2/SAMS were characterized by FTIR, SEM, TG and XRD, stability of VC solution of Ca(IO3)2/SAMS were also systematically measured. The embedding mechanism of Ca(IO3)2/SAMS were proposed according to various analysis results. The results showed that Ca(IO3)2/SAMS were spherical with a particle size of about 20-40 μm and a large number of calcium iodate were in crystalline form on the surface of Ca(IO3)2/SAMS. The half decomposition rate time (t50%) of vitamin C was 54.8 min and 78.3 min by the calcium iodate or Ca(IO3)2/SAMS, respectively. It were demonstrated that the stability of Ca(IO3)2 in feeds were improved significantly.