Abstract: | H2TiO3 was dissolved in the mixture of hydrogen formed peroxide and ammonia under the pH range of 8–10 with a transparent yellow solution formed. When an equivalent mole of Ba2+ solution was added into the yellow solution, the precipitate produced was the peroxide precursor of barium titanate. The cubic nanopowder of barium titanate was obtained when the precipitate was washed, stoved, and then calcined at 600°C for 1 h. The peroxide precursor of barium titanate and barium titanate nanopowder prepared were characterized to be BaTi(H2O2)2O3 by TGA‐DTA, XRD, TEM, SEM, and XREDS. The peroxide precursor of barium titanate was determined to be BaTi(H2O2)2O3. The particle size of the barium titanate nanopowder, the calcined product of BaTi(H2O2)2O3, was in the range of 20–40 nm. A formation mechanism of the barium titanate nanopowder through thermal decomposition of its peroxide precursor was proposed and then validated. |