The invention discloses a 
lysine-modified benzofuroxan compound, a synthetic method, an application and a 
recovery method of the 
lysine-modified benzofuroxan compound as well as a method of detecting the concentration of 
copper ions. The 
structural formula of the 
lysine-modified benzofuroxan compound is shown in the specification. The synthetic method of the lysine-modified benzofuroxan compound comprises the following steps: 1) carrying out reaction on 
methanol, 
thionyl chloride and lysine to obtain lysine methyl 
ester hydrochloride; 2) in the presence of an acid binding agent, carrying out reaction on the lysine methyl 
ester hydrochloride and 4-
chlorine-7-nitro-benzofuroxan, and carrying out 
column chromatography; and 3) dissolving the product obtained in the last step in alkali liquor, extracting for multiple times, regulating a pH value of a water phase, extracting for multiple times, collecting an extractant layer, and carrying out purification. The method of detecting the concentration of the 
copper ions comprises the following steps: 1) drawing a 
standard curve; 2) detecting and recording; and 3) carrying out calculation. The 
recovery method of the lysine-modified benzofuroxan compound comprises the following steps: adding a complexing agent 
aqueous solution into the compound solution containing the 
copper ions, uniformly mixing, extracting, collecting an organic phase, and removing a 
solvent. The lysine-modified benzofuroxan compound is applied to preparing a copper 
ion fluorescent probe. The synthesized lysine-modified benzofuroxan compound is capable of specifically detecting the copper ions, can be prepared into the probe and can also be recovered.