lonic polymer-metal composite(IPMC)is a new flexible smart material,but its mechanism is not clear and its displacement tracking is difficult.In view of the obvious hysteresis nonlinearity and modeling difficulties of IPMC cantilever beam device under low frequency AC drive voltage,this paper tests the actuation characteristics of IPMC cantilever beam under low frequency AC voltage,and analyzes the gain and phase of IPMC at 0.1~10 Hz and 2～5.5 V. The third order transfer function model from driving voltage to actuating displacement is established by Levy identification method.Based on the established transfer function model,a pieceby-step modeling method of IPMC's nonlinear equivalent circuit and first-order transfer function is proposed,which improves the defect that IPMC's equivalent circuit model cannot predict the actuated displacement.The results show that under the low frequency sinusoidal drive voltage of 0.1～5 Hz and 2～5.5 V,the IPMC cantilever device can be replaced by equivalent circuit + first-order transmission.The overall error is less than 0.3 mm,and the average relative error is 2.89%,which meets the application conditions.It can be used for low-frequency AC use of IPMC to improve IPMC displacement tracking accuracy.