Benefiting from ultra-high sensitivity of Hyper-CEST method, 129Xe biosensors possess an obvious advantage in sensitivity over other MRI sensors. However, due to its indirect detection mode the Hyper-CEST spectra resolution is relatively low limiting chemical shift to be an effective indicator in traditional NMR. In order to solve this problem, a 129Xe biosensor based on a new “turn-on” strategy is designed, which exhibits high detection specificity for an enzyme diamine oxidase (DAO). This 129Xe biosensor possesses very high detection sensitivity, and can be tested in Small intestinal villus epithelial cells. Using this strategy, lots of disease-related enzyme can be detected.