A thermo-poro-elastic constitutive model of unidirectionally fiber-reinforced composite materials is suggested by extending the unmixing-mixing scheme which is based upon composite micromechanics. The strain components of thermal expansion due to a temperature change, gas pressure in pores, and chemical shrinkage are included in the constitutive model. On purpose to verify the derived constitutive relations, the representative volume element of two-dimensional lamina subject to various loading conditions is analyzed by the finite element method. The overall stress and strain responses are obtained, and compared with the predicted values by the unmixing-mixing scheme. The numerical results show the usefulness of the proposed model to predict the thermoelastic behavior of porous composites.