A pineapple harvesting robot consisted of a manipulator arm, an end-actuator, a positioning identification device, a frame, a fruit box, a traveling mechanism and a control system was put forward. Four degrees of freedom, including X, Y, Z axis translations and a wrist rotation were required for pineapple picking. A cartesian-coordinate mechanism scheme for the manipulator arm was designed. A sliding-lever double-fulcrum structure was selected for the clamping mechanism of the end-actuator. The cutting device was designed. Pro/E software was applied for establishing 3-D parametric model of parts, assembling parts or components. By setting constraint relations among parts or components, general assembly model of the harvesting manipulator was built. Through several times of simulation with different motion parameters, repeated result analysis and dynamic interference check, optimized structure and working parameters of the pineapple harvesting manipulator was obtained.