Electric charge usually changes some properties of condensation nuclei. These phenomena are important for cloud condensation nuclei (CCN) and cloud droplet concentration in natural and industrial processes. To explore the relationship between the microphysics of CCN and the macroscopic phenomenon of cloud droplet concentration, the Raoult’s effect and electric charge should be considered, which affect the cloud droplet concentration by reducing the saturated water vapor pressure required for growth on the droplet surface. On the other hand, the polarization in nucleation promoted by the charge is considered, which is also regarded as affecting the cloud droplet concentration. In this paper, the equivalent surface tension is proposed to predict the changing trend of cloud droplet population.