The bilinear finite element methods on appropriately graded meshes are considered both for solving singular and semisingular perturbation problems. In each case, the quasi-optimal order error estimates are proved in the -weighted H 1 -norm uniformly in singular perturbation parameter , up to a logarithmic factor. By using the interpolation postprocessing technique, the global superconvergent error estimates in -weighted H 1 -norm are obtained. Numerical experiments are given to demonstrate validity of our theoretical analysis.