A graph is said to be planar if it can be drown in the plane so that no two edges intersect exceptrn(possibly) at their ends vertices.It is of practical interest to able to determine whether a graph isrnplanar or not, our interest is how to check whether the graph is planar or not . In this projectrnwe present the proof of Kuratowski's theorem on planarity of graph and discuss examples on thernapplication of the theorem.