In　this　paper,　a　thermodynamically　consistent　chemo-thermo-mechanical　coupled　constitutive　relationship　is　developed　based　on　the　local　energy　conservation　equation,　the　entropy　inequality　and　mass　conservation　equation,　and　the　constitutive　relation　for　chemo-mechanical　coupled　problem　was　degraded　when　the　temperature　was　kept　constant.　The　governing　equations　of　chemo-mechanical　coupling　model　were　established　by　combining　the　force　balance　equation　with　the　Fick　diffusion　equation.　Then　we　considered　a　case　of　a　sphere　with　symmetrical　boundary　and　initial　conditions,　and　the　diffusion　conducted　along　the　radial　direction.　Using　the　symmetry　of　the　spherical　structure,　the　chemo-mechanical　coupled　governing　equation　was　simplified,　and　then　analytically　solved　by　the　separation　variable　method.　The　analytical　expressions　of　concentration　and　displacement　were　obtained,　and　the　variations　of　stresses,　concentration,　displacement　and　chemical　potential　with　time　were　deduced.　The　results　showed　that　the　deformation　of　the　sphere　and　species　diffusion　was　not　independent,　but　interacts　with　each　other.　The　chemical　potential　in　the　sphere　could　be　affected　by　both　of　them.