Abstract:Angular positioning accuracy is an important factor for fiveaxis machine tool. Due to the restriction of the machine tool structure, it’〖KG-*2〗s difficult to measure efficiently and accurately with traditional methods.The Renishaw laser angle interferometer with indexing table was taken as the research object, the measurement principles of angular error was described. Using synchronous controlling the movement of rotary axis and linear axis, the operational principle and key technology of measuring angular error on nonorthogonal rotary axis were explored, the relational model of typical nonorthogonal rotary axes during test was obtained. Experiment on B axis of a millingturning processing machining center was completed; main factors affecting measurement accuracy were analyzed, then countermeasures were proposed in order to minimize such errors. As a result, this method can be extended to other types of laser angle interferometer as a general method,and can be used on fiveaxis machine tool with multistructure, improving the portability and efficiency.