Planetary gear trains can be used as the transmission systems with high reduction ratio for power machinery. The purpose of this paper is to propose an algorithm for the kinematic design of planetary gear trains with high reduction ratio. Based on the concept of train value equation, we propose a new representation to present the kinematic relationship of the members of the train loop. According to this representation graph, we propose an efficient algorithm for the kinematic design of planetary gear trains with high reduction ratio. Three design examples are designed to illustrate the design algorithm. Based on the proposed algorithm, all planetary gear trains with high reduction ratio can be synthesized.