Ytterbium-doped Tin Oxide Nano-powers were prepared by chemical co-precipitation method using SnCl4•5H2O and Yb(NO3)3•6H2O as precursors and NH3•H2O as precipitant. The effects of processing parameters on the particles were investigated. These parameters include reaction temperature, calcine temperature, kinds of dispersant. The Ytterbium-doped Tin Oxide precursors were studied by means of TG-DTA. The product particles were characterized by means of X-ray diffraction(XRD) and scanning electron microscopy(SEM). The optimized conditions for preparing nanometer Ytterbium-doped Tin Oxide powers were proposed:reaction temperature of 60 ℃, calcine temperature of 600 ℃, non-ionic dispersant of PEG-600.