The fluid dynamics of a vertical metal-organic chemical vapor deposition (MOCVD) reactor for the growth of ZnO film have been studied. The relevant transport equations were solved by numerical integration using a finite volume difference method. Computation results show that the deposition rate strongly depends on the operating parameters of the MOCVD reactor. Simulation results show that the reactor pressure has effect on the deposition rate, which becomes larger with the increment of the reactor pressure in the range of low pressure in our study. The simulated deposition rate is observed to increase firstly and then decrease with the main carrier gas flow rate. The computational study demonstrates that the distance between the O-2 inlet and substrate in the vertical MOCVD reactor plays a key role to obtain a balance between the deposition rate and the uniformity of films across the substrate. The optimization of the MOCVD operational parameters has been applied in the MOCVD growth of high-quality ZnO epilayers. (c) 2007 Elsevier B.V. All rights reserved.