Abstract: The paper presents a high robust BP algorithm using the nonlinear of multilayer feedforward neural networks and based on the series parallel model of the dynamic BP network. In contrast to the conventional BP algorithm,five advantages of the robust BP algorithm are:(1) fitting to the dynamic identification of nonlinear system;(2) the identifical accuracy is very high;(3) not interpolating all the training points;(4) it is robust against gross errors and measuring errors;(5) its rate of convergence is improved since the influence of incorrect sample is gracefully suppressed.The algorithm is applied to the dynamic identification of nonlinear system and the simulation result shows the new method is efficient.