  Perturbative N=2 non-renormalization theorem states that there is no
perturbative correction to the Kahler potential \int d^4\theta
K(\Phi,\bar{\Phi}). We prove this statement by using the N=1 supergraph
techniques. We consider the N=2 supersymmetric U(1) gauge theory which
possesses general prepotential F(\Psi).
