Fatigue crack propagation is the chief style leading to the damage of engineering components. With the design change of modern engineering structure from conservative “safe-life” to “endurance/damage limit”, it brings new big contradiction. Bigger risk occurs when serving time of components extends to maximum. Regular NDT (Nondestructive Testing) methods cannot monitor the initiation and expansion process of short cracks inside components effectively. As an advanced NDT method, ICT (Industry Computed Tomography) has some particular advantages which regular NDT methods do not have. As a result, adopting the latest achievements on industry CT and fatigue fracture, this paper presented a new supervision method for short fatigue cracks propagation based on density field analysis. Experiments have proved that our proposed method could be a new way to inspect the components’ damage in service even to predict their life.