The　paper　summarizes　various　models　adapted　to　unsaturated　soils,　including　elasto-plastic　models,　damage　models,　generalized　suction　models,　thermodynamical　models　and　models　based　on　theory　of　mixtures.　The　elastoplastic　models　in　the　paper　are　categorized　into　three　parts:　Models　that　do　not　consider　the　influence　of　degree　of　saturation;　Models　that　consider　the　influence　of　degree　of　saturation　but　not　hysteresis;　Models　that　consider　hysteresis.　Some　new　methods　of　developing　constitutive　models　for　unsaturated　soils　using　thermomechanics　and　mixture　theory　are　introduced.　Some　advices　on　the　development　of　constitutive　models　for　unsaturated　soils　are　given　in　the　end.