Based on the structures and composition of ceramic materials, the microstructure design and new preparations were used to induce in situ grain growth by adjusting the main factors which had impacts on grain morphology. By adding CAS (CaO-Al2O3-SiO2) and Nb2O5, the complex toughened alumina ceramics with columnar grain was fabricated under pressureless sintering systematically. The influences of additives on the alumina ceramics with columnar grain were analyzed by means of TEM, SEM, XRD etc. The dynamic conditions of anisotropic growth of columnar grain were researched, and superior growth in some grain directions was induced by doping CAS and Nb2O5. The growth mechanism of columnar grains of alumina ceramics was explored, and established growth model.