This study proposes a new method using Euler parameters and quaternion algebra for the kinematic synthesis of an RRSS spatial motion generator. The proposed method is compared with the other method using rotation angles for two-position and three-position motion guide problems. It is found that the proposed method provides solutions better in most cases tested here because the synthesis equations in the method include no trigonometric functions. The solutions converge more easily than in the other method as well as avoiding rotational singularity problems encountered otherwise.