The dynamical properties of cavity optomechanical system are investigated for an initial state composed of squeezed vacuum state and number state. The effect of system parameters on the linear entropy and Wigner function is analyzed. The numerical results indicate that the Wigner function for mechanical mode can be effectively manipulated by adjusting the value of squeezing factor r. Especially, increasing the value of r can enhance significantly the entanglement between cavity mode and mechanical mode. Both negativity depth and region of the Wigner function for optical mode decrease with increasing the value of the mechanical mode parameter k.