A novel amino-anchored sulfonic acid functional heteropolyacid ionic liquid ([NHSO]3PW12O40) wasdesigned, synthesized and used as a catalyst in the Baeyer-Villiger (BV) oxidation of cyclohexanone tosynthetic e-caprolactone (e-CL). The catalyst was well characterized by FT-IR, XRD, 1H NMR, XPS, TGDTAand SEM analysis methods, which showed that the tungsten phosphate anion (PW12O403) was successfullymodified from the sulphonate-functionalised IL precursor NHSO and formed a new hydrogenbond between the introduced –NH2 group and PW12O403. The combined effect of ionic bonds and hydrogenbonds contributed to the good stability of the catalyst. Catalyst activity evaluation experiments confirmedthat [NHSO]3PW12O40 exhibited superior performances such as a cyclohexanone conversion of86% and e-CL yield and selectivity of 82% and 95%, respectively. Furthermore, [NHSO]3PW12O40 couldbe recovered by simple treatment and the activity of the catalyst did not decrease significantly after fivereplicae experiments. In addition, the reaction kinetics and mechanism of the catalyst were investigatedand a simple validation was given in conjunction with the bond energy changes of the catalyst during thereaction. The innovative of the green, stable and high-performance functionalised heteropolyacid IL catalystprovides a new solution for the efficient production of e-CL.