Developing　an　effective　method　for　separation　of　NH3　from　N2,　H2　and　CO2　is　highly　desired　not　only　for　the　advancement　of　Haber-Bosch　process,　but　also　for　protection　of　the　environment.　Here,　we　report　synthesis　of　carboxylic　functionalized　mesoporous　polymers　by　copolymerization　of　divinylbenzene　(DVB)　and　acrylic　acid　(AA)　through　a　one-pot　solvothermal　route.　The　mesoporous　structure　and　acidic　site　concentration　of　these　polymers　can　be　adjusted　by　changing　the　amounts　of　monomers　used.　Such　polymers　display　fast,　highly　efficient　and　selective　adsorption　of　NH3　that　is　better　than　that　of　most　other　solid　sorbents　in　the　literature,　especially　in　terms　of　NH3　adsorption　selectivity　against　N2,　H2　and　CO2.　The　adsorption　of　NH3　by　these　polymers　is　also　highly　reversible,　making　them　promising　solid　sorbents　for　production　of　high-purity　NH3.