In order to evaluate enterprise informatization maturity accurately and effectively, an improved particle swarm optimization algorithm based on BP artificial neural network is developed. Based on analyzing the working principle of particle swarm optimization algorithm, the improved algorithm encodes its particles, formats its fitness function, and updates its particle speed and position, improves it though immunization information process mechanism; Then, paper integrates particle swarm optimization algorithm with BP neural network algorithm and redesigns the training steps for the improved algorithm. Finally, the evaluation indicators of enterprise informatization maturity are analyzed and the improved algorithm is realized. The simulation results illustrates that the algorithm has better self-adaptability and can simplify model structure, increase algorithm efficiency, and improve evaluation accuracy when used for evaluating enterprise informatization maturity.