Abstract: When loss-of-coolant accident (LOCA) occurs in the nuclear power plant, a lot of mass and energy are released into the containment. The temperature and pressure in the containment can be lowered down effectively by initiating the spray system. Considering the changes of the volume, mass, temperature and drag coefficient, the characteristics of heat and mass transfer of the spray droplet to the surroundings were obtained by calculation using the convective heat and mass transfer correlations. The comparison between the calculation results and the TOSQAN experimental data shows good agreement. The cases with different droplet diameters, different environmental pressures and the case with the steam not reaching saturation state were calculated. By analyzing the effect of the spray, the results can offer theoretical basis for the spray system design and application.