The lattice mismatch between LiAlO 2 and GaN is only 1.4%, so LiAlO 2 is expected to be a promising substrate for the epitaxy of GaN. In present work, large sized and transparent LiAlO 2 single crystal has been grown by using temperature gradient technique. The crystal quality was characterized by the methods of chemical etching, optical microscope, TEM and synchrotron source X ray topography. The results showed that LiAlO 2 grew along 〈100〉 direction when it crystallized without using seed in Mo crucible. The crystal was free from bubbles and inclusions, and the dislocation density measured on (100) crystal plane was about (3.8￣6.0)×10 4 cm -2 . The main defects were subgrain boundaries, which may be caused by the fluctuation of temperature field in the furnace or over high growth rate. These two parameters should be optimized in further.