Objective To study the preparation method of magnetic fluids and its antitumor effect in combination with paclitaxel thermo-chemotherapy in vitro. Methods Magnetic fluids were prepared by copre-cipitation and modified by sodium oleate. Transmission electron microscopy, Fourier infrared spectroscopy and other instruments were used to characterize the products. The heat effect was studied under ahemating magnetic field in vitro. MTT assay was performed to examine the effect of magnetic fluids in combination with pachtaxel thermo-chemotherapy of human cervical cancer cells Caski. Results The prepared magnetic fluids were global with a diameter of 20～30 nm,Zeta potential was -11 mVto -16 mV. They had distinct heat effect in a alterna-ting magnetic field and could rise to a temperature for tumor thermo-chemotherapy (41 ～ 46℃). Thermo-ehem-otherapy could significantly inhibit the proliferation and promote of the Caski cells, which were more distinct than the magnetic fluids hyperthermia and paclitaxel chemotherapy. Conclusion Magnetic fluids in combina-tion with paclitaxel thermo-chemotherapy has advantages of chemotherapy and hyperthermia. This treatment shows better effects on cell experiments than that of using paclitaxel chemotherapy alone and may provide a new way in clinical treatment for human cervical cancer.