The invention discloses a luminescent crystal material with a function of selectively detecting Fe<3+> ions, and a preparation method of the luminescent crystal material. The chemical formula of the luminescent crystal material is [Zn(OBA)(3-abit)]n; the luminescent crystal material belongs to a triclinic crystal system; a space group of the luminescent crystal material is P-1; the unit cell parameters of the luminescent crystal material are as follows: a equals to 11.1092(4) angstroms, b equals to 12.9619(4) angstroms, c equals to 14.1041(5) angstroms, alpha equals to 73.382(2) degrees, beta equals to 76.088(2) degrees, gamma equals to 80.229(2) degrees, and Z equals to 2; the structural formula of the luminescent crystal material is shown in the description. The preparation method comprises the following steps: adding zinc nitrate and 4, 4'-oxybisbenzoic acid into a water solution, and stirring; adding 4-amino-3,5-bis(imidazole methyl)-1,2,4-triazole into a methanol solution, and stirring; putting the obtained water solution of the zinc nitrate and the 4, 4'-oxybisbenzoic acid into a reaction tube, adding a buffer solvent into the reaction tube, then slowly adding the methanol solution of the 4-amino-3,5-bis(imidazole methyl)-1,2,4-triazole into the reaction tube, and sealing; after that, crystallizing, filtering, washing, and drying to obtain the luminescent crystal material [Zn(OBA)(3-abit)]n. The luminescent crystal material prepared by the method has a selective detection effect for the Fe<3+> ions, and has good chemical and optical stability.