There are several methods determining an appropriate performance grade of virgin binder, which is re(erred as design binder, in RAP contained bituminous mixture design process. However, difficulties have been experienced in utilizing the methods in the field application in Korea, because SHRP binder test, the key tests to determine a design binder, requires well-trained personnel, high price equipment, and time consuming process. Thus, the study investigated the relationship among the binder aging level, RAP contents, and rheologica1 properties of binder. The study results provide mix designer with a simple method in selecting an appropriate grade of virgin binder.