By simple microwave irradiated solvothermal process using microwave oven Cadmium Selenite (CdSeO3) nanoparticles were prepared. Cadmium acetate and Sodium selenite were used as precursors in the molar ratio 1:3. The powder XRD result shows that particles are purely crystallized in hexagonal phase with the broadening of diffraction peaks attributed to nanoscale size of the particles. The dielectric measurements were carried in two frequencies for temperatures ranging from 40 to 150oC. The present study indicates that the polarization mechanism in the nano particles considered is mainly contributed by space charge polarization. It can be understood that the space charge contribution plays an important role in the charge transport and polarizability in all the systems considered in the present study. The dielectric constant, dielectric loss, AC conductivity and DC conductivity increases with increase in temperature.