A new tripodal ligand, N, N, N′, N′, N″, N″ hexaisopropyl 2, 2′, 2″ nitrilotris (2,1 ethoxy) triacetamide (L) and its new erbium picrate complex were prepared. The structure of the complex was determined by X ray crystal structure analysis. The result reveals that the Er 3+ is encapsulated by the three arms of the tripodal ligand, and nine coordinated by the bridged head nitrogen atom, all ether oxygen atoms and carbonyl oxygen atoms of the ligand, and two oxygen atoms of the bidentate picrate. The coordination polyhedron is a distorted mono-capped square antiprism. A new tripodal ligand, N, N, N ’, N’, N “, N” hexaisopropyl 2, 2 ’, 2 "nitrilotris (2,1 ethoxy) triacetamide (L) and its new erbium picrate complex were prepared. of the complex was determined by X ray crystal structure analysis. The result reveals that the Er 3+ is encapsulated by the three arms of the tripodal ligand, and nine coordinated by the bridged head nitrogen atom, all ether oxygen atoms and carbonyl oxygen atoms of the ligand, and two oxygen atoms of the bidentate picrate. The coordination polyhedron is a distorted mono-capped square antiprism.