In the present paper, a space-arrangement system of structural element for multiple degree-of freedom parallel mechanisms with consideration of mutual interferences among structural elements such as links and pairs is investigated. In order to determine optimum profiles of links which satisfy the maximum working space of the end effector, a rotary plane which is arbitrary fixed on one of the moving link in the mechansim is introduced, and rdative loci of intersection points of the other moving links with the plane are analyzed. Moreover, conditions to determine link arrangements avoiding mutual interferences of moving links are formulated. Applying the above-mentioned system, a spatial six-DOF parallel mechanism with consideration of interferences among moving links is synthesized as a practical example.