In order to solve the problems of low accuracy of commonly used time series prediction algorithms and difficulty in tuning parameters, a load prediction method was proposed based on a multilayer bidirectional long short-term memory (BiLSTM) neural network. The method includes network model design, adaptive parameter setting, and improved particle swarm optimization (PSO). The data was input into the BiLSTM network model for training and uses an adaptive algorithm for automatically parameter adjustment. The method uses a model evaluation method based on the benchmark model to calculate the fitness of the improved particle swarm optimization algorithm. The method uses improved particle swarm optimization to optimize the prediction results of the model. The average absolute percentage error of this method was reduced by 3.6% to 7.2% compared with several typical forecasting algorithms, and the training time was reduced by more than 10%, Through experimental comparison with a variety of typical time series prediction algorithms. Experimental results show that the method has higher accuracy and stronger applicability in time series forecasting, and provide an important scientific basis for the use of load forecast results for elastic expansion and contraction.