Abstract: The linear guide is an important connection structure of machine tools. There is no effective method to calculate and evaluate the overall accuracy of linear guide connection structure in the existing research. The equivalent model of the linear guide connection structure is proposed based on the finite element theory ,and the deformation characteristics of which are analyzed and calculated. With the homogeneous transformation matrix theory, the accuracy characteristic calculation and evaluation method of the linear guide connection structure is established. By the method, the performance calculation and accuracy analysis on the linear guides of a vertical machine tool are carried out. To evaluation the performance of the linear guide, The influence on the accuracy of load, slider position and initial error is analyzed, finally the feasibility of the model is demonstrated.