Abstract: The crystal of diethylthanolammonium bis (o-diphenol) antimonate (Ⅲ)belongs to orthorhombic space group P₂₁₂₁₂₁ with unit cell constants:a=9.096Å, b=11.636Å, c=17.786Å and Z=4. The coordinates of Sb atoms were derived from three-dimensional Patterson function and the locations of non-hydrogen atoms from succesive Fourier and difference Fourier syntheses.The structure was refined to R=0.0326, R_w=0.041 for 2106 independent reflections. It was considered that Sb atom makes use of four sp³d hybrid orbitals to conbine with four O Atoms in formation of a pesudo-trigonal bipyramidal configuration.