On the basis of studying shield machine and planetary transmission, to address cutting drive system of shield machine, a novel dual drive planetary transmission system with large capacity is presented, and its principle and structure are analyzed. Through establishing a new kinematical model of the transmission system and analyzing its characteristics, the transmission ratio, rev and torque relationship and changing rules within the system are acquired. By comparing the simplified experimental results with theoretical results，it is shown that the variation is basically the same, which verifies the correctness of the model and analysis method. The high-power dual-driven planetary gear transmission system with great transmission ratio, strong carrying capacity, can perform the function of low-speed and high-torque output, and meet basic requirements of shield machine. It can not only replace the traditional multi-driven transmission system, but also achieve the transmission function in three different types of shield machine.