There is a relationship between demographic stability or changes and planning for economic, social and cultural development, because it is mainly impossible to plan development without complete demographic information. In every society, population passes the stages of demographic stability, stagnancy, development and expansion, re-stagnancy and decline in terms of population growth or no-growth. There are several views about demographic changes: theories of demographic growth, decline, stability and proportionality. Acceptance of each theory requires an appropriate demographic policy. After the victory of Islamic Revolution, the dominant discourse, approach and demographic policy in Iran were based on population decrease. Today, however, this country adopts the policy of population growth.Having reanalyzed and criticized demographic theories and policies, the present paper proposes the theory of "proportionality of population" appropriate to territorial conditions. Furthermore, the strategic policy of Islam about population is qualitative and quantitative population growth with regard to territorial conditions and existing facilities, with the aim of empowering Islamic society and fulfilling the aim of creation.