Aiming at the problems that BP(Back Propagation) network which needs long training time and weak astringency, and that the robustness of RBF(Radial Basis Function) neural network is susceptible to the structure of hidden layer, the GRNN(Generalization Regression Neural Network) method is presented to detect weak harmonic signal under the noisy chaotic background. In this method, GRNN is used to build one-step predictive model for chaos background first, and then the frequency way is combined to process pre...