The manufacturing industry is the foundation of national development. With science and technology developing, precision turning technology has gradually become one of the cutting-edge technologies of advanced manufacturing technology. In the paper, the turning mechanics model is established based on the principle of metal cutting, and the corresponding cutting force is calculated. Considering the cutting force, material weight, flange weight, and other loads, the analysis model of the CK61125 machine tool spindle is constructed based on the finite element method, and the corresponding maximum strain and modal solution are calculated. The results are that when the 30, 000 N load is applied, the largest strain of the spindle is 0.0013 mm/mm, and the largest stress is 265 MPa. When the 100, 000 N load is applied, the strain of the spindle largest is 0.0015 mm/mm, and the stress is 290 MPa. The four orders of vibration modes of the spindle are obtained, which are 215.3 Hz, 256.2 Hz, 436.33 Hz, and 974.5 Hz. By comparison with the experiment, the spindle vibration frequencies are 87.8 Hz and 625 Hz, while the spindle rotating testing speeds are 100 rpm, 500 rpm, and 800 rpm.