Yttria stabilized zirconia nanopowders have been prepared by co-precipitation method using a microwave radiation in the process of drying following calcination at various temperatures (400-800°C). Effect of the calcination temperature on structural and fractal characteristics of zirconia nanopowders was studied by nitrogen adsorption and small-angle X-ray scattering. With increasing temperature, the particle size increases, whereas the surface area decreases. We found that for solids calcined at temperatures in the range of  400-800°C the surface fractal dimension is nearly constant, whereas the mass fractal dimension increases. We present theoretical and experimental study to establish a relation between the fractal dimension of zirconia nanopowders and the pre-exponential factor of the rate constant of the CO oxidation. Our results indicate that the pre-exponential factor of the rate constant decreases with increasing the mass fractal dimension. We show a good correspondence between theoretical and experimental results.