Abstract: A six degrees of freedom serial-parallel manipulator with a three-rotation parallel mechanism and a three degrees of freedom serial mechanism (two-prismatic plus one-revolute) was synthesized and investigated according to the theories of the structure synthesis of robot mechanisms. It is able to perform spatial transformational movement, rotation, hoisting, tilting, planar rotation and tilted rotation. Based on configuration analysis, kinematic position equations were formulated, kinematic model of parallel fine-tuning structure was discussed as a key and inverse position analysis and velocity mapping equations were presented. Kinematic simulation of the mechanism was conducted using MATLAB software. A case study was provided, which applied the mechanism in tunnel erector assembling manipulators. The proposed mechanism possesses large work-space volume, high rotational flexibility, sound stability and balance, high precision and robust load capacity, and can be applied in robot system of planting and picking, as well as of forest cutting and transport.