Abstract: The theory of homogeneous transfer matrix (HTM) are applied in establishing the kinematic error model of 5-axis NC machining tool with two-axis turntable, and the model is simplified.A method of kinematic error deviation in this type of 5-axis NC machining tool based on telescoping double ball bar is developed to measure the kinematic error.Six kinds of simultaneous three-axis control motions with two translational axes and one rotary axis are designed to identify the deviations.In the measurement, telescoping double ball bar is used to measure the relative distance between the spindle and the worktable in the motion of 5-axis NC machining tool.Finally, measured value of telescoping double ball bar is substituted into the model to obtain kinematic error of 5-axis NC machining tool.This method has greatly simplified the whole process of calculation of mathematical model and error deviation.From the simulation, it has been confirmed that the proposed method gives precision results and is able to apply to the measurement of 5-axis machining tool effectively and conveniently.