A new three-dimensional copper dithiocarbamate-copper iodide coordination polymer [Cu(Me2dtc)2(CuI)3]n (Me2dtc=N,N-dimethyldithiocarbamate) was synthesized by reactions of Cu(OAc)2,NaI and Na(Me2dtc) in DMF solution,characterized by elemental analysis,IR spectrum,and single-crystal X-ray diffraction. The crystal belongs to the monoclinic system,space group C2/c with a=1.293 89(17) nm,b=1.077 61(11) nm,c=1.456 05(17) nm,β=115.585 (4)°,V=1.831 1 (4) nm3,Z=4,Dc=3.175 g·cm-3,Mr=875.28,λ (Mo Kα)=0.071 073 nm,μ=10.082 mm-1,F(000)=1 604,the final R=0.029 5 and wR=0.081 7. A total of 2 083 unique reflections were collected,of which 1 918 with I>2σ(I) were observed. The Cu atoms are Cu(Ⅰ)/Cu(Ⅱ) mixed-valence and they have two different coordinate geometries,namely planar square and tetrahedron. This three-dimensional structure consists of individual Cu(Me2dtc)2 molecules linking together CuI polymeric chains which run parallel to the [001] direction vis Cu-S bonds.