Here, we observed decomposition of crystal ice on graphene substrate under controlled electron beam dose through cryo HR TEM. It is well known that electron beam influence during observation by TEM is rather volumetric rather than surface. However, according to our observation, the decomposition of hexagonal and cubic ice was analyzed and compared to the power law relationship. The result suggest that decomposition initiated from each facets of both cubic and hexagonal particle. In addition, the bulk crystallinity was maintained, only changing its size which gives an evidence of primary damage in radiation damage. These observations give an evidence for exceptional stability under electron beam compared to other beam sensitive materials and we expect further research regarding to this property.