Composite hollow spheres with IPN structure were synthesized by swelling polymerization against a PS hollow sphere.After modification,carboxyl group was introduced to the shell.The polymeric gel can induce a favorable growth of various components forming composite/polymer hollow spheres without the removal of any template.Various functional composite hollow spheres such as silica/polymer,titania/polymer and palladium/polymer were prepared by this method.After removing polymer,silica and titania hollow spheres can be obtained.