This study proposes an optimization method based on error analysis for ball screw transmission six-DOF platform (BSTSP). The error model of BSTSP has been built up based on the simpler error source model. According to the error model, the upon platform outputting error influenced by structural parameters has been computed. And the preferable range of the structural parameters is preliminarily identified. Then the upon platform outputting error is set as optimization objective function. The structure of BSTSP is optimized by using ADAMS based on error analysis. The optimal analysis results provide an important basis for improving the space position accuracy of BSTSP.