The vibration fatigue analysis model of the key suspension parts of bogie was established, the stress power spectrum of key suspension parts bases on modal stress was obtained by modal superposition method, and the probability distribution function of the structural stress-strain range was deduce, moreover, the fatigue life of the structure was obtained in the condition of IEC 61373 standard spectrum and measured acceleration spectrum as the excitation by using the linear fatigue damage criterion. The results showed that the critical fatigue damage value of the suspension structure was 1.58 after three-direction acceleration of each incentive 5 hours of IEC 61373. Under the actual measured excitation of the acceleration of the Wuhan—Guangzhou line, the fatigue life was 2.97 million kilometers. The analysis method based on modal stress effectively indicated the relationship between the excitation frequency and the vibration frequency of the structure itself, by which the more accurate fatigue life prediction could be obtained.