In this paper, we extend an improved multi-component pseudopotential lattice Boltzmann model to simulate the dynamics of droplets with large density ratio and relatively large kinematic viscosity ratio. This improved model is validated to be feasible to simulate multiphase flow via examples of the stationary droplet, the droplet oscillation process, and the droplets collision. The results indicated that the improved model is effective for simulating multi-component multiphase flow with small spurious current. The spurious current reduces to 0.0072, which is much smaller than the spurious current (0.033) of the same order of magnitude density ratio in literature. For the droplet oscillation process with large density ratio, the numerically predicted oscillation period by the improved model is 2400, which agrees well with the analytical result. Finally, the droplets collision process with different impact parameters are studied by this improved model. It shows good agreement between the simulated results and the existing experimental results.