The invention relates to a 
fluorescence probe for detecting 
intracellular hydrogen sulfide and a preparation method and application of the 
fluorescence probe. Cy7 fluorochrome and 
sodium acetate are dissolved in 
anhydrous dimethylformamide (DMF), heating 
reflux is carried out for 2-4 hours under protection of Ar gas, cooling and suction 
filtration are carried out on an obtained mixture, 
mother liquor is crystallized under the low temperature of minus 4-20 DEG C, and keto form 
cyanine reddish brown crystals are obtained after the suction 
filtration; toluoyl 
benzoic acid and 
oxalyl chloride are dissolved in 
anhydrous CH2Cl2, then a bit of DMF is added, mixing is carried out for 2-6 hours under the temperature of 0 DEG C, and toluoyl 
benzoyl chloride is obtained; and keto form 
cyanine and 
triethylamine are dissolved in the 
anhydrous CH2Cl2 and are cooled to be 0 DEG C, the toluoyl 
benzoyl chloride is added dropwise, mixing is carried out for 10-30 minutes under the temperature of 0 DEG C, the mixture is heated to be in the 
room temperature, mixing is carried out overnight, suction 
filtration and 
spinning drying are carried out, separation is carried out through a 
chromatographic column, green solids are obtained after the 
spinning drying, and the 
structural formula is as follows. The 
fluorescence probe is simple in composition, high in detection speed, free of long-term incubation in a detection process, high in sensitivity, and capable of detecting 
intracellular endogenic 
hydrogen sulfide.