Composites　containing　saturated　fluid　are　widely　distributed　in　nature,　such　as　saturated　rocks,　colloidal　materials　and　biological　cells.　hi　the　study　to　determine　effective　mechanical　properties　of　fluid-saturated　composites,　a　micromechanical　model　and　a　multi-scale　homogenization-based　model　are　developed.　In　the　micromechanical　model　the　internal　fluid　pressure　is　generated　by　applying　eigenstrains　in　the　domain　of　the　fluid　phase　and　the　explicit　expressions　of　effective　bulk　modulus　and　shear　modulus　are　obtained.　Meanwhile　a　multi-scale　homogenization　theory　is　employed　to　develop　the　homogenization-based　model　on　determination　of　effective　properties　at　the　small　scale　in　a　unit　cell　level.　Applying　the　two　proposed　approaches,　the　effects　of　the　internal　pressure　of　hydrostatic　fluid　on　effective　properties　are　further　investigated.