Abstract: Aiming at problem of the high infection rate of respiratory diseases on cruise ships and the corresponding lack of quantitatively research, the Computational Fluid Dynamics(CFD) method is adopted in this paper to analyze the droplet transmission and dispersion process coughed by an infected passenger accommodated in an enclosed cabin quantitatively.The air flow equation is solved by solving the unsteady Reynolds averaged Navier-Stokes equations while the Eulerian model is used to simulate the coughed droplet dispersion.The controlling effects for reducing the droplet concentration are also investigated under various conditions of changing ventilation modes and increasing ventilation rates.The results show that the displacement ventilation mode is superior to the mixed ventilation mode when increasing the ventilation rate to control the droplet dispersion.The mixed ventilation mode needs at least three air changes to empty the droplet, while the displacement ventilation mode needs only two, and the reduction of averaged droplet concentration obeys exponential distribution.In addition, the sleeping gestures of the infector have big influences on the droplet concentration in the breathing zone and inhaled dose of the susceptible.