For observation of parasitic reaction effect during InAlN material growth by Matel-Organic Chemical Vapor Deposition (MOCVD), the growth parameters include temperature and pressure had been varied to investigate it. The pressure would be kept at 50torr, 100torr and 150torr and temperature was varied from 700 °C to 780 °C by 20 °C step in each growth pressure. The experimental results appeared that higher pressure gave rise to more serious parasitic reaction during material growth. It made the less Al atoms incorporate into the AllnN. In addition the 100-torr growth pressure shows the best efficiency of Al atom incorporation compare with other two growth pressures. By the AFM analysis, the morphology of Al0.82In0.18N grown with three different pressures was also examined.