In order to obtain the optimal alignment accuracy of 3-PPR parallel platform, aiming at the impact of platform structure and work influencing factors on its alignment accuracy, the theoretical error analysis and experimental verification method are used to study the alignment accuracy of the platform. The mathematical model of the platform error was obtained and the alignment accuracy of the platform was best when the speed is 7.5 mm/s and the acceleration is 100 mm/s2. The above analysis results provide the necessary theoretical basis for further improvement and development of the platform performance, which has certain practical application value for all kinds of high-precision alignment occasions.