In this paper, an SIR model (Susceptible – Infected – Recovered) for Conjunctivitis is proposed and analyzed. Ill the present investigation of the dynamical transmission of Conjunctivitis the effect of rainfall is taken into account. The standard method was applied to analyze the behaviors of the model. Analytic results showed that there were two equilibrium points; disease free equilibrium and endemic equilibrium point. The qualitative results are depended on a basic reproductive number (R0). We obtained the basic reproductive number by using the next generation method and finding the spectral radius. Stabilities of the model are determined by using Routh-Hurwitz criteria. If R0 <1, then the disease free equilibrium point is local asymptotically stable: that is the disease will died out from the community, but if R0 > 1, then the endemic equilibrium is local asymptotically stable: that is the disease will occur in the community. The numerical results are shown for supporting the analytic results. We concluded that the rainfall is effected on the spread of this disease, to bring the epidemic under control more quickly, it is most important to educate the people in the community on the correct prevention method.