Abstract: The magnetic nanosized Fe3O4/TiO2 composite was prepared by cladding directly nanosized TiO2 colloids on the surface of magnetic iron oxides. The structure and properties of this kind of composite were characterized by XRD, XPS, SEM, FT-IR and the multiple physical property method system (PPMS) for magnetic materials. The results show that the best preparation conditions for the kind of composite were stirring time of 2 h and stirring rate of 350 r·min-1. The nanosized TiO2 colloids showed a good cladding effect to magnetic iron oxide because of electrostaic attraction. The prepared composite particles were sphere with an average particle size of 56 nm and good monodispersity, whose saturated magnetization was 3.5 A·m2·kg-1 and coercivity was 1 750 A·m-1.