The work aims to analyze the stiffness and harmonic response of package parallel mechanism of 2-UPR-SPR which has three degrees of freedom including two turns and one move, thus researching the stiffness and anti-vibration performance of the mechanism, with respect to the special application requirement of high working precision in the process of automatic packaging. The 3D entity model was established by SolidWorks and then imported into software Ansys Workbench for analysis. The displacement deformation cloud of the mechanism under three different postures on the action of external force was obtained. Through the modal analysis, the natural frequencies from first order to sixth order of 130.39, 133.42, 218.35, 760.36, 768.07, 776.96 Hz and the vibration mode of each order frequency of the 2-UPR-SPR parallel mechanism were obtained. On the basis of modal analysis, the displacement response curve of platform along x, y, z directions was deprived by harmonic response analysis. The weak position of mechanism stiffness can be seen, and the rule of the change of stiffness with the position is obtained. The anti-vibration performance of the parallel mechanism is proved by harmonic response analysis, and the sensitive frequency that the mechanism should avoid is got. It lays the foundation for further dynamic design and optimization of the package parallel mechanism.