The gear transmission is widely used in various kinds of stable and high performance environment, its transmission error is the main error source that affects transmission precision. By using the theory of dynamic transmission error of gear and the virtual instrument technology, integration of high precision grating angle sensor, a set of composite measurement test bed was built which could be used to measure single tooth meshing and the whole case (gearbox)transmission error. It has the advantages of fitting actual conditions,high degree of automation, strict test beat and high accuracy.The test results prove that the test system can be used to measure gear and gearbox transmission error fast and accurately. It provides reference for transmission gear modification and optimization of machine performance.