The invention discloses a 
rare earth organic framework material for 
fluorescence detection of trace water and a preparation method of the 
rare earth organic framework material. The 
rare earth organic framework material is an orderly microporous crystalline material, and the general 
structural formula of the material is [(CH3)2NH2]2[Ln6(mu3-OH)8(L-NH2)6(H2O)6]*(G)7, wherein Ln in the formula is Eu<3+>, Tb<3+> or Gd<3+>, L-NH2 is a chainlike 
phthalic acid organic ligand with an amino 
group function group and G represents a 
solvent in pores. The rare earth organic framework material is synthesized with a solvothermal method, the synthesis method adopts a simple process, the condition is mild, the yield is higher, and the product stability is good. The rare earth organic framework material has the properties of characteristic emission of rare earth and 
fluorescence of the ligand, the specific value of two emission peaks and the content of water in the 
solvent are in a better 
linear relation, and ratio type detection of trace water can be realized; the light color remarkably changes with the change of the 
water content, and the material can be used for colorimetric type detection of trace water. The sensitivity of a probe is high, the response speed is high, the 
detection limit is low, and the material can be recycled and is expected to be used practically in fields of detection and monitoring of trace water.