Ontology evolution refers to the process of modifying ontology in response to a change in its conceptualization. This activity is joined to measuring inconsistencies and effects propagation on objects depending to ontology. In this paper, we propose a propagation estimation of ontological change effects in large ontology. The propagation approach uses the graph properties to estimate impact degree of a change in another entity of the ontology. The approach determines also the vulnerability rate of an ontological entity to a change in the community on ontology to which it belongs.