Graphical measures such as closeness, average length, the eccentricity of a vertex estimates how fast the flow of information would be through a given node to other. In this paper, we analysing networks and aim is to find the most important nodes in a network. Thereby in a social network we can evaluate whether combinations of symptoms or addition of other symptoms can better classifypersons for assessing any criteria.Also, we study the betweenness centrality of a vertex that measures the collision domain in a network.