Magnetic Fe3O4@TiO2 (TiO2 coating Fe3O4) nanocomposite with high whiteness had been successfully prepared through the in-situ systhesis of nanosized crystalline TiO2 on the surface of nanosized Fe3O4 particles at low temperature (60 degrees C), using titanyl organic compounds (TOC) as the precursor. The as-prepared samples had been characterized with FTIR, UV-Vis, XRD, XPS, SEM, DLS and PPMS (Physical Property Measurement System). The experimental results proved that there were the chemical bond links (Fe-O-Ti) between Fe3O4 and TiO2, when the TOC/Fe3O4 mass ratio was 5, reaction time 2 h, 350 rpm, 5% TOC and 1% Fe3O4, the as-prepared magnetic Fe3O4@TiO2 nanocomposite had an outstanding dispersibility with the particle size of about 40-45 nm, the saturation magnetization intensity 49.2 emu/g(-1), and the coercivity 152 Oe, which met ideally the practical demands in some applications, such as the magnetic paper.