A new type of branched chain 3PRRS six degree of freedom parallel mechanism applied to virtualaxis hexapod machine was studied. The closed vector equation of 3PRRS parallel mechanism was established, a kinematics model was built. The speed relationship between input and output was got by derivation.The MATLAB software was used to build the speed curve.ADAMS software was used to build the dynamic model of 3PRRS parallel mechanism. The simulation results are consistent with theoretical analysis,shows that the correctness of the theoretical analysis.The speed relationship between input and output was used to analyze the boundary singular and variable substitution was used to get the singular trajectory analytic expression,And the computer simulation was used to describe the singular trajectory, it provides an important theoretical guidance for the trajectory planning and control of the parallel mechanism applied to the virtualaxis hexapod machine.