The invention discloses a multi-response azacyclic formaldehyde fluorescent probe molecule with the structure shown in formula I and its preparation method and application. The molecule realizes the selective and quantitative recognition of formaldehyde through the fluorescence analysis method, and is used in automotive interior materials, health Carry out testing and evaluation of formaldehyde, copper ions and sulfide ions in the fields of home furnishing, biomedicine, etc. It can also be used for fluorescence imaging of biological samples, and can also be used as an ultraviolet absorber for plastics, coatings, inks, displays, lighting, glasses, daily use Chemical industry, textiles and other technical fields, in addition, the multi-responsive azacyclic formaldehyde fluorescent probe molecule provided by the present invention has strong fluorescence emission performance in solution and solid state, and can be used as a fluorescent material for anti-counterfeiting technology, light conversion Materials, fluorescent labels, fluorescent imaging, etc.: wherein, R is H or Cl, and X is CH or N.