The propagation of fatigue short crack is a fractal curve, the irregular path can be described by fractal dimension. The fractal dimension of the crack implicit in many of the physical factors, such as microstructure of material, load conditions and so on. In this paper, the short crack for low cycle at high temperature is studied. The material 20# steel in the various stress state is experimentally studied, the initiation, propagation and coalescence influence of short crack are observed. By analyzing experiment results, characters of crack fractal dimensions evolving with the cycle process are as follows, the behavior of short fatigue cracks satisfies fractal feature, with the development of the fatigue process, the fractal dimension is increased.