Neodymium ion doped TiO2 nanoparticles were prepared by sol-hydrothermal process using titanium isopropoxide as the TiO2 precursor. The prepared neodymium ion doped TiO2 nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The photocatalytic degradation of 1,4-dichlorobenzene (DCB) was conducted in the suspension of Nd3+ doped TiO2 nanoparticles. The photocatalytic behaviors and microstructure of the prepared Nd3+-TiO2 nanopowder were investigated as the function of dopant content. The effect of Nd3+ content of the doped TiO2 nanoparticles on the DCB photodegradation reaction rate was investigated and the first order reaction rate constant (k = 0.153min(-1)) for the doped nanoparticles was found to be significantly lamer than that for the undoped TiO2 nanoparticles. The result showed the optimum value of the Nd3+ content to be 2 mole %.