Abstract: 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.