Abstract: The classic k- model is used to study the turbulent mixing induced by Rayleigh-Taylor instability. In the model, turbulence is driven by its pressure and density gradients instead of its velocity gradient. The expression of the turbulence production term reasonably describing the characteristics of Rayleigh-Taylor instability is given. Experiments of Youngs et al and Kucherenko et al under constant and variable accelerations are simulated by this model. The results are compared with detailed experiment data to prove the validation of the model closure, model constants, numerical algorithm and the implementation of the model used in the paper. On the basis of these, the influences of the density ratio of two materials, the value of acceleration and deceleration time on turbulent mixing are further investigated.