In this note, a new polynomial identification method for the Hammerstein system is proposed. The method employs the results of nonparametric statistics and best approximation theory, obtaining a polynomial form estimate of the nonlinearity in the system. Except continuity, no conditions are imposed on the nonlinearity. The uniform as well as global convergence of the method is established. The rates of convergence in both cases are derived under mild conditions on the smoothness of the nonlinearity. The method is especially suitable for identifying the controlled plants with the description of Hammerstein systems.