The present invention discloses a two-stage process for preparing functionalized magnetizable microspheres. The first stage includes forming an inner shell of styrene polymer or styrene copolymer around magnetizable nano particles having a monolayer of a non-water-soluble dispersing agent coated thereon. The second stage includes forming an outer shell of styrene polymer or styrene copolymer with sulfate (SO.sub.4.sup.-) bounded thereto around the inner shell by free radical polymerization. Preferably, nano particles of a noble metal are deposited on the surface of the outer shell. The magnetizable microspheres prepared by the process of the present invention have a size of 100-1000 nm, and the thickness ratio of the inner shell to the outer shell ranges from 10:1 to 1:10.