A new 3d-4f heterometallic polymer {[Sm2Cu(PDC)2(SO4)2(H2O)6]·2H2O}n 1 has been synthesized by Sm2O3, Cu(SO4)2·5H2O and pyridine-3,5-dicarboxylic acid under hydrothermal conditions. The compound crystallizes in triclinic system, space group P1, with a = 6.352(7), b = 10.040(10), c = 10.315(11) , α = 94.958(14), β = 95.556(7), γ = 99.747(14)°, V = 641.7(12)3, Z = 1, Mr = 1030.63, Dc = 2.651 Mg/m3, μ = 5.615 mm-1, F(000) = 491, the final R = 0.0491 and wR = 0.1345 for 2098 observed reflections with I 2σ(I). The compound is a three-dimensional network structure in which infinite lanthanide-carboxylate chains are linked by [Cu(SO4)2]2- metalloligands to form a mixed-metal coordination network.