Crosslinked starch was prepared from corn starch and epichlorohydrin.Then the amphoteric starch with high degree of substitution was synthesized by semi-dry method.With amphoteric starch, ferrous chloride and ferric chloride as raw marerials,magnetic amphoteric starch composite microspheres were prepared by mixed coprecipitation. The composite microsphere was characterized by IR, SEM and VSM, and the results showed that the composite microsphere was irregular, with rough surface and an average particle size...