Based on the analysis of the existing spindle rotary precision measuring methods, a twopoint method was researched for spindle rotating precision test. Firstly, under the dryload conditions of spindle, the spindle rotating error was tested by using “Standard ball” method, then sampled at fixed spot on the neck of spindle by using “Vertical layout style twopoint method”, and got spindle roundness error at corresponding spot by subtracting spindle rotating error from sampling data. Secondly, under the machining conditions of spindle, the spindle was sampled at fixed spot by using “Vertical layout style twopoint method”, from above, and by subtracting the above tested spindle roundness error already known from sampling data in real time, finally the spindle rotating error was gotten under machining conditions. The results show that the proposed method of “Twopoint method” for test of rotation precision of spindle is effective and feasible.