The invention discloses synthesis and application of a fluorescence-enhanced fluorescent molecular probe for rapidly detecting hydrogen sulfite ions or sulfite ions. The structural formula of the fluorescent molecular probe is shown as FORMULA (1). The fluorescent molecular probe for rapidly detecting the hydrogen sulfite ions or the sulfite ions, provided by the invention, has the advantages of high response (15 s), low detection limit (48 nM), high selectivity, high sensitivity, suitability for naked eye detection, wide pH application range and the like, and can be applied to detection of the hydrogen sulfite ions or the sulfite ions in living cells; the fluorescent molecular probe is not interfered by negative ions such as AcO-, CO32-, F-, Cl-, Br-, HCO3-, NO3-, S2O32-, HS-, SO42-, HPO42-, H2PO4-, PO43-, SCN- and the like; even in the presence of interfering ions, the fluorescent molecular probe also has good response to the hydrogen sulfite ions or the sulfite ions and has the detection limit as low as 48 nM, so that the fluorescent molecular probe is a very sensitive detection system; the fluorescent molecular probe can be applied to analysis and imaging of the living cells, so that the fluorescent molecular probe has a potential practical application value in the fields of biochemistry, environmental science and the like.