The research status of machine tool’〖KG-*2〗s linkage error test was analyzed. The test principles of double ball bar and 2D encoder KGM were presented. Aiming at a type of vertical machining center’〖KG-*2〗s X-Y plane, circular error tests were done and the influences of feeding speed and radius were analyzed. Circular tests were done at 500, 1 000 and 3 000 mm/min by double ball bar and the circular error data of different feeding speed were gotten. Error separation was done, the errors elements and its sequence of different feeding speed were gotten. Ten circles with different radius were tested by KGM and the circular error data of different radius were presented. Finally, circular cutting was done with an Aluminum workpiece by conventional milling and climb milling modes and the test results were compared with KGM’〖KG-*2〗s test results.