Dynamic error motion of the spindle system has great impact on the machining accuracy of the precise machine tool. It can improve the maching precision of the machine tool and provide data support for the next generation of product research through error testing and finding the error sources. The causes of the error of the spindle system and different forms of the rotary errors affect the performance of boring machine each processing were discussed, quantifiable indicators were used to evaluate the error motion. The varitation trend of the radial-fixed,radial-rotating, axial-fixed and tilt sensitivity of the spindle system were analyzed from a type of precise horizontal coordinate boring machine. The result shows that the speed of the spindle has great impact on the dynamic error motion and the error motion is obvious without load and with high speed. It needs to choose suitable speed according the need of the precision of the parts that need to be machined.