The present invention designs and synthesizes a fluorescent sensor capable of single and selective recognition of L-arginine, which first uses 4,4´-biphenol and hexamethylenetetramine as substrates in a trifluoroacetic acid solvent The reaction produces 4,4´-biphenol derivatives; and then reacts in absolute ethanol with isoniazid and 4,4´-biphenol derivatives as substrates to obtain the target fluorescent sensor FINH. DMSO‑H in fluorescent sensors 2 O solution, respectively add L-glycine, L-alanine, L-valine, L-leucine, L-isoleucine, L-methionine, L-proline, L- Tryptophan, L-Serine, L-Tyrosine, L-Cysteine, L-Phenylalanine, L-Asparagine, L-Glutamine, L-Threonine, L-Asparagine amino acid, L-glutamic acid, L-lysine, L-arginine and L-histidine, and found that only the addition of L-arginine can enhance the fluorescence of the fluorescent sensor FINH, thus realizing Highly sensitive and single selective recognition of L-arginine.