Graph labeling has wide applications in the modelling and problems comes under the areas like Radar,Communication networks,Circuit design, Coding theory, Astronomy,Xray, DatabaseManagement, Crystallography and Modelling of Constraint Programming over Finite domain.So study on strong edges of labeled graphs has more importance.In this thesis I invented Strong Graphs,Properties of Strong labeled Graphs,A family of Strong Graphs,Nishad Graph,Properties of Nishad Graph,Nishad's Algorithm,Properties of Nishad's Algorithm, Application of Nishad Graph,Strength of a labeled Graph,Weak Graphs and weakness of a labeled graph,A family of weak graph and Nishad's Method to find the strength and weakness of labeled Graphs.