Based on the study of endgrinding with bowlshaped CBN wheel, this paper shows a grinding spindle system designed for high efficiency deep endgrinding. Static characteristics and impact factors of spindle unit are analyzed by theoretical calculation and numerical simulation, and it verified the rationality of spindle structure and parameters. Based on the theory of modal analysis, modal test of the grinding wheel spindle system was performed by hammering method, and the first six order modal parameters are obtained and analyzed. Those are also the dynamics characteristics analysis of grinding spindle. Results show that the grinding spindle system could meet the technical requirements for the high efficiency deep grinding. Finally, the grinding test platform was built by applying the developed grinding spindle unit, and some experiments are carried out to study the high efficiency deep grinding. With conditions of 80100 m/s grinding wheel speed, an endgrinding test is conducted on a Cr12Mo1V1 workpiece, as a result, cutting depth 0.1750.5 mm, Ra 0.83.2 μm and cylindricity 510 μm.