Friedman’s image charge method has been implemented in molecular dynamics simulations on water droplet systems to represent the reaction field. The simulation were first done on pure water droplets with and without the reaction field. The energy, radial distribution function, surface effects, and dielectric constant of the droplets were analyzed. Second, the hydration free energy of a model cation was calculated in different water droplets with and without the reaction field. For pure water droplets with the reaction field, we found that the inherent problems associated with droplet boundary conditions, i.e., the surface effects and the low dielectric constant of the droplets, can be only partly alleviated by the reaction field. From the free energy calculations, we found that the reaction field can well represent the long-range interaction when the cation is at the center of a droplet. However, the hydration free energy of the cation in the reaction field depends on the position of the cation in the droplet, in a similar way as without the reaction field. All this suggests that direct application of Friedman’s image charge method to droplet simulations is not successful. In the study, we found that by neglecting the interaction between water molecules and their images and not applying the reaction field to the water molecules near the surface, the hydration free energy can be made almost independent of the position of the cation.