Abstract: The natural frequency of the variable cross-section leaf spring with composite materials embedded shape memory alloy (SMA) fibre is studied. The restrained recovery characteristics is discussed based on Brinson constitutive model. A solution procedure for the natural frequency of the leaf spring is given by Rayleigh-Ritz method after deriving the constitutive equation of SMA fibre anisotropic laminated beam. The variable curves of natural frequency with temperature, ply angle and volume fraction of SMA fiber are presented using MATLAB numerical calculation. The adjustable mechanism of natural frequency of variable cross-section composite leaf spring with SMA fiber is revealed.