Abstract: Using Sr(NO3)2, ［CH3(CH2)3O］4Ti and KOH as raw materials SrTiO3 nano-powders were prepared by hydrothermal method. The effects of surface-active agent content on the crystal phase, morphology, grain size and polarity of the SrTiO3 powders were studied by XRD, SEM, laser particle size analyzer. The result indicate that the addition of surfactant SPAN80 did not affect the crystal structure of SrTiO3 powders and reduced the agglomeration of the powders. the spherical SrTiO3 powders with grain size of 39 nm were prepared on the best addition amount of 10vol.% SPAN80. The polarity of nanometer SrTiO3 powders coated with a layer of SPAN80 changed from polar to non-polar.