Abstract: Under the stress ratio of 0.1, 3 different loads were constantly loaded on 3 groups of compact tension specimens of ADB610 low carbon bainite steel to study the growing of the fatigue crack. The a-N test data of crack length a and the cycle life N were obtained from the tests, and the fatigue crack growth rate was calculated by fitting the a-N test data with the seven point fitting method. The resuts showed that when the load was low, the cycle fatingue life was long; in the first phase of growth of fatigue crack, the fatigue crack growth rate of the low-load was relatively low, however, with the fatigue crack developing gradually, the rate of low-load fatigue crack growth would be the higest.