To understand the mechanism of aluminium nitride (AlN) film growth is of great importance for its potential applications. In this paper, we investigate the growth behaviour of the AlN film by using the computational fluid dynamics program FLUENT. It is found that the gas flow has a great impact on the temperature field. By equipping the aluminium boat area with a graphite ring and adjusting the heating power appropriately, the desired temperature field can be achieved. The simulation also shows that the V/III can have a significant impact on the deposition behaviour. With a V/III of 10, the trend of the curve is abnormal which is significantly different from the other curves. The distance between the inlet and the substrate is changed. It is found that with the increasing distance, AlN deposition rate decreases and the uniformity becomes better. Besides, when the operating pressure is changed, it is found that the operating pressure can also greatly affect the temperature field.