Abstract: In response to the demand for ultra-precision machining with high-efficiency and high-surface quality ultra-precision of high-end optical elements, a four-axis (XZBC) ultra-precision machine tool was developed. To validate the machine design performance, the finite element model of the whole machine and key functional components were established by Ansys Workbench, and then carry out static analysis, modal analysis and harmonic response analysis. The first six natural frequencies and modal shapes of the machine tool, hydrostatic guideway and spindle were obtained by the modal analysis of the working conditions, among which the base frequencies of the whole machine, hydrostatic guideway unit and spindle unit were 102.24, 0 and 5.76 Hz respectively. To further master the actual response of the key components spindle, harmonic response analysis was performed on the spindle unit using the modal superposition method based on the modal analysis. The resonance-sensitive frequencies of the spindle unit were 288, 294, 387, 405 and 414 Hz, and the deformation displacement is within 0.02 μm. The sensitive frequencies and the corresponding displacement response are obtained by the frequency range of the displacement and strain response curves. It verifies the rationality of the machine tool and spindle structure design under the actual working condition, and lays the theoretical foundation for structural optimization of ultra-precision machine tools.