A new mixed complex [Zn(tren) (H-SSA)] was synthesized based on the reaction of ZnO,5-sulfosalicylic acid and tren in water-methanol mixed solvents where tren was tris(2-aminoethyl)amine for the first time. The structure of the mixed complex was characterized by elemental analysis, IR, 1H NMR and thermal analysis. The crystal structure of the complex was also determined by X-ray single crystal diffraction. Its crystal belongs to trigonal system with space group P31, a=1.109 67(18) nm, b=1.109 67(18) nm, c=1.236 8(4) nm, V=1.318 9(5) nm3; Dc=1.616 g·cm-3; Z=3; F(000)=666; μ=1.553 mm-1. CCDC: 253908.