Abstract: Based on Suzuki's immersed boundary lattice Boltzmann method, an improved approach is proposed. By adopting the force model of the lattice Boltzmann method and improving the technique of fluid structure interaction force calculation, the process of calculating the force of fluid structure interaction is simplified. Moreover,its calculation time is over 50% shorter than that of the original method, which means that efficiency is greatly improved. Based on the improved method, such features as lift coefficient, drag coefficient,pressure coefficient and flow field are discussed under different conditions of flow over a rotating cylinder. Compared with the related results, this new improved method is shown to be accurate and reliable.