Abstract: Using crude materials of industrial product TiCl₄, ordinary reagent Sr（NO₃）₂, and KOH, by adding surface active agent dodecylbenzenesulphonic acid （DBS）, the nanosized SrTiO₃ particle modified with a layer of DBS were successfully prepared through the hydrothermal method and their microstructure were characteried. FTIR, DAT and TG were used for the determination of the components. It can be proved that the nanosized SrTiO₃ were capped by a layer of DBS. The sizes, shapes and crystal phase were determined by TEM and XRD. The results indicate that the product are cable phase, small crystal (size distribution and Little agglomeration. The average size of the powders is about 120nm. The average she of layer of DBS is about 6nm. In contrast with the bulk SrTiO₃. The polarity of nanometer SrTiO₃ powder wass changed by coating with a layer of DBS.