Abstract：This paper identified natural frequencies using artificial neural network. Theory of artificial neural network and a method of natural frequencies identification were introduced firstly. Then the numerical simulation for identification natural frequencies of benchmark structure that was set up by the IASC-ASCE Task Group on Health Monitoring was carried out. In the simulation, the training patterns and the testing patterns were computed by the FEA program. Discrete frequency response function was input of neural network and the natural frequencies were output of neural network. Finally, the testing results under several noise levels were compared. The result of study show that it is feasible able to identify the natural frequencies using artificial neural network.