The 54SiCr6 spring had not reach the standard but broke. The cracked spring and spring material were analyzed. The results show that the main reasons for spring fatigue failed are serious uneven decarburization on the surface of the raw material and mixed crystal. So in future， heating temperature， annealing temperature and uniformity of the billet should be controlled strictly to prevent decarburization on the light material surface. Preclude the small ratio of surface drawing＋polishing process， restore skin production process， control heat temperature and finishing rolling temperature to prevent mixed crystal.