A process for preparing perovskite-type compound Ax(BO3)y powders involving reacting a solution containing A and a solution containing B, or a combined solution comprising A and B, with an alkaline solution in a high-gravity reactor at a temperature ranging from about 60° C. to about 100° C. A is one or more metal elements selected from the group consisting of Li, Na, K, Mg, Ca, Sr, Ba, Pb, Sm, La, Nd, Bi, and other rare-earth metal elements. B is one or more metal elements selected from the group consisting of Ti, Zr, Sn, Hf, Nb, Ce, Al, Zn, Mn, Co, Ni, Fe, Cr, Y, Sc, W, Ta, and the like. The resulting mixture is then filtered, rinsed and dried to obtain the desired powders. The obtained perovskite-type compound Ax(BO3)y powders have a small average particle size with a narrow particle size distribution, a perfect crystal form and a uniform particle shape, and is suitable for use as raw material for making dielectric, piezoelectric, anti-ferroelectric, pyroelectric, pressure-resisting, sensing, microwave media, and other ceramics.