The prediction method on flow and thermal performance in the cooling unit of automobile air conditioning systems was investigated. The two- and three-dimensional flow in the model unit based on the actual cooling unit was numerically solved by the modified FLIC (Fluid In Cell) method. The effect of the air flow maldistribution on the thermal performance of the evaporator was predicted by using the air flow distribution calculated about the model unit. Some experiments were performed to confirm the above numerical procedures. It is shown that both predicted results are in good agreement with the measured data.