A　1D　copper-containing　organic-inorganic　hybrid　heteropolyoxoniobate,　H3[K(H2O)6][K2(H2O)10]2[Cu(en)2(H2O)2][Cu(en)2(Nb6O19Cu(en))2]center　dot　24H2O　(HPONb　1),　has　been　synthesized　to　heterogeneously　catalyze　Knoevenagel　condensation　at　room　temperature　with　high　yields　and　cycling　stability.　The　catalyst　presents　the　best　catalytic　activity　for　Knoevenagel　condensation　among　the　polyoxometalates　(POMs)　reported　to　date.　A　1D　copper-containing　organic-inorganic　hybrid　heteropolyoxoniobate　catalyst　for　efficient　catalysis　of　Knoevenagel　condensation　at　room　temperature.