Pure and MgO doped near stoichiometric lithium tantalate has been grown by adding flux method. The observation of the crystal wafers etched by hydrofluoric acid under metallographic microscope indicate that the domain structure of near stoichiometric lithium tantalate is hexagonal. Polarization experiments have been done by using the equipment made by ourselves. By using short-impulsed polarization electric field, several parameters, including the positive and negative direction coercive force field and polarization time were investigated. Polarization current and entirely reversed domain structure were obtained.