Chemo-mechanical　coupling　phenomenon　exists　in　the　polymer　gel,　biological　tissues,　clay　soils　and　so　on.　The　chemical　excitation　can　induce　deformation　of　materials.　A　theory　framework　for　chemo-mechanical　coupling　behavior　is　presented　and　a　numerical　procedure　is　established　for　simulation　of　the　chemical　and　mechanical　interaction.　Based　on　the　thermodynamics　law,　the　constitutive　relationships　of　chemo-mechanical　coupling　behavior　are　given.　The　equivalent　integral　and　weak　forms　of　the　governing　equations　are　obtained　by　using　weighted　residual　method.　This　investigation　contributes　to　understanding　of　the　coupling　mechanism　of　chemical　and　mechanical　behavior　in　heterogeneous　materials.