Abstract: Ultra-fine magnesium titanate powder was prepared by mechanochemical method with basic magnesium carbonate and titanium oxide as raw materials.The material′s crystal topography，solid phase transformation and thermal stability during the preparation were investigated by scanning electron microscope，X-ray diffraction，laser particle size analyzer and differential thermal analysis.Results showed that with the ball-milling the particles of the mixture powder became smaller rapidly，homogeneous powders with the size of 2~5 μm were obtained after ball-milled 30 h.The crystal structure of mixture had been destroyed by high energy grinding.Along with the rising of grinding time the specific surface area of the mixture increases.After ball-milled 30 h，the mixture transferred into amorphous and single phase MgTiO↓3 crystal was obtained after heat treatment.The synthesis temperature of MgTiO↓3 had been lowered from 1 000 ℃ to 700 ℃ because of the grinding mill.