Abstract: Precursor was obtained from raw materials of bismuth nitrate and titanic chloride at analytical pure level.Then bismuth titanate nanopowders were prepared through hydrothermal method by adjusting pH at 8 ~ 9.Effect of different types and concentrations of mineralizer on the phase composition of bismuth titanate nanopowders was analyzed by XRD.Results showed that compared with ammonia,potassium hydroxide is a better mineralizer for forming bismuth titanate crystal phase.Pure orthogonal bismuth titanate powder was obtained when the concentration of potassium hydroxide was from  1.0 mol/L to 2.0 mol/L.Whereas,bismuth titanate phase could not form with ammonia as mineralizer.TEM and SEM were used to observe morphology of the powder.TEM result showed that the width and length of bismuth titanate crystals were  30 nm and 100 nm,respectively.Besides SEM result showed that bismuth titanate crystals aggregated to some degree.