Smart　hydrogels　are　environmentally　sensitive　hydrogels,　which　can　produce　a　sensitive　response　to　external　stimuli,　and　often　exhibit　the　characteristics　of　multi　filed　coupling.　In　this　paper,　a　hydrogel　rod　under　chemo-mechanical　coupling　was　analytically　studied　based　on　a　poroelastical　model.　The　already　known　constitutive　and　governing　equations　were　simplified　into　the　one　dimensional　case,　then　two　different　boundary　conditions　were　considered.　The　expressions　of　concentration,　displacement,　chemical　potential　and　stress　related　to　time　were　obtained　in　a　series　form.　Examples　illustrate　the　interaction　mechanism　of　chemical　and　mechanical　effect.　It　was　found　that　there　was　a　balance　state　in　the　diffusion　of　concentration　and　the　diffusion　process　could　lead　to　the　expansion　or　the　stress　change　of　the　hydrogel　rod.