A 3-TPS(RRR) hybrid machine tool that could process vertically as well as horizontally was designed in Northeastern University. A parallel locking mechanism, equipped between the moving platform and the fixed base, is used to constrain partial degrees of freedom (DOF) of the platform. It leads that the platform has three translational DOF and a rotate DOF. The kinematic analysis was discussed in this paper. Several important issues were addressed, namely, position, velocity, acceleration, Jacobian matrix. A simulation was also carried out, which lay the base on structural design and dynamic analysis.