In order to solve the problem of current electric cylinder test system and test method can’t meet the requirements of electric cylinder performance test，a parameter measurement system is designed in the paper and it contains industrial computer as upper machine，and Leisai DMC5480 movement control card as center controller，and high precision magnetic grid ruler as detection device. Firstly，an open automatic test system and test method for electric cylinder and function test module are designed for the system. Then，combining with data detection device，by the VB and API function library，the paper designs open hardware structure and software platform for the system，which includes location accuracy，return error，repeat positioning accuracy，error analysis and compensation，and error analysis and compensation as well. The system has been successfully applied to the electric cylinder parameter measurement of a company.