An one-dimensional time dependent cylindrical model of cumulus clouds is used for studing the growth of cloud droplets by condensation in this paper. The characteristics of condensation spectra of cloud droplets formed under the condition of various spectra of condensation nuclei and turbulence exchanges have been compared. The results show that the giant nuclei with radii 1.5-2.5 μ play an important role, in the formation of large droplets by condensation. The existence of nuclei larger than 2.5 μ only sli...