A new model for predicting the small-crack growth rates is proposed under the constant amplitude loading. With the use of two important parameters, the transition crack length a(0) and the barrier characteristic parameter d*, the new model can reflect the abnormal feature of small-crack growth. The effect of crack closure is considered in the model as well. The model is shown to provide a better correlation to the experimental results for the Ti-6Al-4V alloy under various stress levels at a stress ratio of R = 0.4.