Lattice Boltzmann method (LBM) is a novel and relative new approach in the field of hydrodynamics and well-suited to efficient high-performance computing implementation. In this thesis, a three-dimensional two-phase lattice Boltzmann model is adopted based on Lee et al. on multi graphic processing unit (GPU) cluster. Such a complex binary system at high density ratio is achieved easily and yields high performance. Here, several numerical validation are examed. First, the spurious velocity appearing near the two-phase interface caused by the force imbalance is successfully eliminated in a stationary droplet case. Droplets oscillation is validated and the results are in good agreement with analytical solutions. The behaviours of two droplets collisions are also investigated. "Coalescence" and "stretching separation" phenomena are observed and studied in terms of two dimensionless variables, Weber number We and impact parameter B, showing good consistency to benchmark. Further, an efficient multi-GPU cluster implementation is proposed and achieves good scalability even in the case with high GPU number.