MgTiO3 precursor was mechanochemically synthesized by high-energy ball milling of MgO and TiO2. The sintering characteristic of the resulted MgTiO3 precursor was investigated. The experimental results indicate that particles of both MgO and TiO2 powders become smaller rapidly, and then the crystalline structures of MgO and TiO2 change significantly. MgTiO3 was observed by XRD after 30 hours of ball milling. Strong diffraction peaks of MgTiO3 were observed after 50 hours of ball milling. HRTEM observation proves that dense MgTiO3 ceramics with a compact crystalline structure can be sintered from mechanochemically activated MgTiO3 precursor, the volume density of the resulting ceramic is as high as 95% of the theoretical density, the porosity and average pore diameter of the ceramic are measured as 4.95% and 50 nm respectively, and the transverse strength exceeded 500 MPa.