The theory of inclusion is introduced in this paper. Two meso-mechanical expressions for the constitutive relations and effective elastic moduli of anisotropic media which include distributed inclusions are derived by self-consistent method. The effective elastic moduli of materials which may include defects or damage can be obtained by the expressions. The theoretical and effective elastic moduli of anisotropic media such as fiber composites are also obtained，thus a relationship between the meso-structures and macro-properties of materials are established by the expressions.