It is the first time ionic liquid was applied to gas solvent sublation, which established a new method for separation/enrichment of tetracyclines (TCs) antibiotic based on ionic liquid gas solvent sublation. The optimizing experimental conditions were as follows: the mixture of ionic liquid 1-hexyl-3-methylimidazo lium hexafluorophosphats and ethyl acetate ([Hmim] PF6-EA, phi = 1/0.9) can be used as flotation solvent, Fe(III) ion was as trapping agent, pH of test solution was 7.6, the gas flow rate was 40 mL x min(-1), and the flotation time was 50 min. The complexes of TCs- Fe (III) were pre-concentrated in the [Hmim] PF6-EA layer and this was used to determine analytes by fluorescence method directly. The linear regression equation was F = 246.5c+4.32 (c: microg x 10 mL(-1)), and correlation coefficient was 0.999 1. Recoveries between 94.2% and 100.4% were achieved from surface water and sediment samples in ponder by using this method and the relative standard deviation of 5 microg x mL(-1) TCs for 5 parallel determinations was less than 3.2%. FTIR spectroscopy demonstrated that no chemical (bonding) interactions occurred between the ionic liquid and the complexes functional groups, and the ionic liquid was only solvent. The experimental result indicated that utilizing ionic liquid to float TCs in environmental sample is feasible.