Abstract: The creep effect of suspensions in electro-dynamic loudspeakers was modeled based on fractional order derivatives. The fractional standard linear solid model (FSLS) was presented by substituting the Abel dashpot for Newton dashpot in Standard Linear Solid (SLS) model. The electrical impedance and the transfer function between diaphragm displacement and input voltage signal of two midrange speakers with different rubber surrounds were measured by Klippel laser analyzer system, and the model parameters were identified by the least-mean-square method. By comparing the fitting results of FSLS model with the other two models- 4 Parameter Logarithmic model and SLS model, the results show that the FSLS model can rightly predict the frequency dependent compliance loss factor and yield higher accuracy for modeling the creep effect in loudspeaker suspensions.