The work aims to analyze the influence of ball joint swinging angle on 6-PSS parallel manipulator workspace, and measure whether the manipulator can accomplish its desired task. The cylindrical coordinate fast search algorithm, combined with the inverse solution, was applied to search the maximum workspace boundary of 6 PSS parallel manipulator. The influence of the maximum ball joint swinging angle on shape and volume of manipulator workspace was analyzed. The calculation results showed that the ball joint swinging angle was the factors mainly influencing the size of manipulator’s reachable workspace in the xy plane. The manipulator’s reachable workspace volume was approximately in linear increase when the ball joint swinging angle was between 5° and 16°, and then the growth tended to flatten out between 16° and 19° and finally remained the same after 19°. It concludes that, if other parameters remain unchanged, the maximum ball joint swinging angle will not affect the size of 6-PSS parallel manipulator workspace after 19°.