Belt dryers have been widely used in the drying process, a key process for quality control, of aquatic feed or pet food. An important criterion to measure the drying quality of a dryer is moisture uniformity, which directly affected by the distribution of airflow field. The airflow field is determined by several factors, including conveyor position and feed thickness. In this study, effects of conveyor positions on airflow distribution in three types of belt dryers are simulated and compared using computational fluid dynamic analysis. The simulation results show that the conveyor positions had significant effects on airflow rate in a two-layer belt dryer. Furthermore, the simulation provided three different airflow fields for three dryer models, and an optimal dryer model was selected for further analysis of air velocity on feed surface.