We investigated the process parameters of the high temperature MOCVD (HT-MOCVD) numerical model for the AlN growth based on CFD simulation using orthogonal test design. It is believed that high temperature growth condition is favorable for improving efficiency and crystallization quality for AlN film, while the flow field in the HT-MOCVD reactor is closely related to the process parameters, which will affect the uniformity of the film. An independently developed conceptual HT-MOCVD reactor was established for the AlN growth to carry out the CFD simulation. To evaluate the role of the parameters systematically and efficiently on the growth uniformity, the process parameters based on CFD simulation were analyzed using orthogonal test design. The advantages of the range, matrix and variance methods were considered and the results were analyzed comprehensively and the optimal process parameters were obtained as follows, susceptor rotational speed 400 rpm, operating pressure 40 Torr, gas flow rate 50 slm, substrate temperature 1550 K.