Within aging rotary painting system for plastic wheel cover, sprayed paint particles caused the quality problem as attached to back surface of the wheel cover by the cyclone vortex in the booth. The purpose of this study is to select the spray conditions to ensure a stable quality of the rotary painting system. For this, simulation for flow characteristics of each spray nozzle have been carried out using ANSYS program, and tested to find the optimum spray condition, such as spray distance, spray pressure and rotation speed by manufactured test apparatus of paint spray. Finally, satisfactory results were obtained by testing with a actual painting system in developed spray conditions.