The dynamic changes of morphology on the { 100} face of EAFP(eucommia antifungal protein) crystals were examined by in situ Atomic Force Microscopy (AFM) in their mother liquor. According to the AFM results different supersaturations are responsible for these morphological changes. At hight supersaturations the EAFP crystals grow very fast and the density of growth steps is very high. At higher supersaturations the formation and development of 2 - D step dominate the growth of EAFP surface. At lower supersaturations the anisotropic spiral dislocations are major growth on the EAFP crystal surface. At very low supersaturations the EAFP crystals grow very slow and there are many holes in the surface which indicate the incomplete growth of the surface. Meanwhile the effects of scanning rate and scanning direction are studied here.