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 Er3+ 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.