关键词: 混沌理论, 预测, 反向传播（BP）神经网络, 遗传算法

Abstract: In order to improve forecasting model precision of BP neural network for chaotic time series，an improved prediction mothod for chaotic time series of optimized BP neural network based on modified genetic algorithm is presented.The modified genetic algorithm is used to optimize the weights and thresholds of BP neural network，and then BP neural network is trained to search for the optimal solution.The availability of this prediction method is proved by predicting chaotic time series of several typical nonlinear systems.Compared with the forecasting results of BP neural network，the computer simulations have shown that the nonlinear fitting and precision of this prediction model are better than those of BP prediction model.

Key words: chaos theory, prediction, Back Propagation（BP） neural network, genetic algorithm