Abstract: A modified elman neural network according to the dynamic & kinematic equations of helicopters was established, the training algorithms for the neural networks(NN) was derived, and the training steps and their realizations were provided. From the telemetry data collection of real trial flights of a type of helicopter, the data of typical flying attitudes were exploited to train the NN and calculate the elements of associated weighted matrix, thus the NN for dynamic analysis against the helicopter was obtained. To illustrate the NN effeteness, the vertical operation response in the constant velocity forward flying attitude was simulated, comparing simulation results with real trial flight data shows that the NN basically reflects the real dynamic behavior of the helicopter.