This paper designed a type of freeform surface roughness measurement bench using parallel-mechanism. The virtual prototype of surface roughness measurement bench has been established. Basic structure parameters and work-space of bench have been calculated according to the program of surface roughness test. An example of bearing outer circle roughness measurement based on Stewart platform has been analysed. From the example of measurement bench it is observed that the designed bench based on Stewart platform can be used as a multi-DOF structure in the freeform surface roughness measurement.