Hydro-Mechanical Transmission System has six basic schemes when the planetary train for power conflux connects to other mechanism with different ways. The paper divides the six basic schemes into two kinds of positive phase and negative phase according to the relationship of output speed and motor speed. If the positive phase planetary train and negative phase planetary train are combined to used as power conflux mechanism, Multi-Range Hydro-Mechanical Transmission System can be realized that has a wide range of infinitely spItalic texteed variable. The paper analyzes the kinematics characteristic and the reasonable value of parameters of planetary train of the eight combined schemes, when the output speed of all ranges follows arithmetic or geometric law. According to the results, the best combined scheme of planetary train for vehicle transmission is determined at last.