Aiming at the problems of large data dimension, more redundant data, and low accuracy in network traffic anomaly detection, a network traffic anomaly detection model (FR-APPSO BiLSTM) based on feature reduction and bidirectional long short-term memory (LSTM) neural network optimization is proposed. First, the feature dimensions are divided by hierarchical clustering according to the similarity distance between data features, and the features with high correlation are divided into the same feature subset. Second, an automatic encoder is used to reduce each feature subset, eliminating redundant information, and reducing the computational complexity of the detection data. Then, a particle swarm optimization algorithm based on adaptive updating of variables and dynamic adjustment of parameters (APPSO) is proposed, which is used to optimize the parameters of the bidirectional LSTM neural network (BiLSTM). Finally, the optimized BiLSTM is used as a classifier to model network traffic anomaly detection using the reduced feature data. Experiments based on NSL-KDD, UNSW-NB15, and CICIDS-2017 datasets show that the proposed FR-APPSO-BiLSTM model can effectively reduce data features, improve the accuracy of detection, and the performance of network traffic anomaly detection.