The recovery force of shape memory alloy spring is described by using polynomial constitutive equation. The nonlinear dynamic model of forced vibration for the shape memory alloy spring oscillator is derived. Numerical simulations are performed by a fourth-order Runge-Kutta method. The bifurcation diagram and Lyapunov-exponent spectrum are presented while the dimensionless temperature, the dimensionless damping coefficient or the dimensionless amplitude of exciting force is varied respectively, thus the bifurcation of the system is investigated. Furthermore, the periodic and chaotic motions of the system are analyzed by means of the displacement time history diagram, the phase portrait, the Poincare section diagram and the power spectrum with different parameters. The results show that the periodic or chaotic motion of the system occur by changing temperature, damping coefficient and amplitude of exciting force, thus the vibration of the system could be controlled.