A new low-cost precise displacement platform without a guiding apparatus was developed to perfect its working performance and to improve the displacement straightness and position accuracy of the system. Based on the theories of parallelogram and proportional lever,the structure of the platform was designed and the work principle was introduced. Then,the movement parts in the platform were analyzed by the Finite Element Method(FEM). Finally,an autocollimator and a high precise measuring head were used in the measurement of the displacement straighness and the the error of the lifting displacement,respectively. The experiment results show that the error of the displacement straighness is smaller than 1" and the error of the lifting displacement is less than 0.02 mm,which shows that the structure achieves the design desire completely. The platform in applications is proved that it is easy to install and maintain and can be used in a weightless condition,so it is suitable for the spaceflight fields and other precise displacement systems.