In order to improve the stability of calcium iodate in feeds，Calcium iodate have been distribu-ted into liquid paraffin at first，then the microsphere of calcium iodate( Ca( IO 3 )2 /SA microsphere) wereprepared by emulsification/internal gelation with sodium alginate as wall material and Nano-calcium car-bonate as cross linker． The Ca( IO 3 )2 /SA microspheres were characterized by FT-IR and SEM，and theinfluence of preparation conditions of Ca( IO 3 )2 /SA microsphere on the loading content of calcium iodate( LC) and encapsulation efficiency ( EE) was studied systematically by the single-factor method． The re-sults showed that the loaded calcium iodate was loaded in crystalline form in microspheres． The optimizedcondition of preparation of Ca( IO 3 )2 /SA microsphere were as follows: sodium alginate concentration12 g·L－1 ，Nano-calcium 1/2，Span80 2%，acid-calcium substance ratio 6. 9∶ 1，calcium iodate mass1. 2 g，oil phase stirring speed 500 r·min－1 ，oil-water volume ratio 3∶ 1，emulsification time 30 min，enrichment time 90 min，crosslinking time 25 min． The loading content ( LC) and encapsulation efficiency( EE) of Ca( IO 3 )2 /SA microsphere in the optimized condition were 41. 0% and 71. 8%，respectively．