A PRR+2-PRRU parallel mechanism with two translation and one rotation was proposed, and its kinematic characteristics were studied.According to azimuth characteristic set theory,the topological characteristics of the parallel mechanism, such as POC set, degree of freedom and coupling degree, were analyzed.The coupling degree of the mechanism is 1, and the configuration is weak coupling design.Analytical method was used to analyze the position, and MATLAB was used to verify the correctness of the position solution. On the basis of position analysis, the mechanism workspace was analyzed and the Jacobian matrix of the mechanism motion was solved. The decoupling characteristics of the input-output control mode of the mechanism were evaluated based on the Jacobian matrix. The result shows that the translational input Y is coupled with the translational output x, and three types of input-output control are decoupling. The velocity and acceleration formula were deduced by Jacobian matrix, and the output motion law of the moving platform of the mechanism was analyzed by ADAMS.