Abstract: The carboxymethyl cellulose（CMC）Fe₃O₄  nano composite particles were prepared in the CMC solution by a modified oxidation deposition method. The properties, structure, and size of the products were characterized by IR, ZP (zeta potential), VSM (vibrating sample magnetometer), XRD and TEM. The results show that CMCFe₃O₄ which dispersed homogeneously in water is inverse spinel structure and the average particle size is 40nm. Carboxymethyl cellulose molecules are chemically adsorbed on the surface of Fe₃O₄nano-particles.The zeta potential of CMCFe₃O₄ is lower than common Fe₃O₄ under the same pH and its saturation magnetization is 36.74emu·g^-1. Filtration coefficient of CMCFe₃O₄ in the soil is approximately 0.03 cm^-1, and 72% of CMCFe₃O₄ suspension could penetrate through the soil column (10cm) under gravity in the soil column tests.