The present invention provides a method for making an adhesive composition. An adhesive substrate comprising at least a first cyanoacrylate monomer is provided and then mixed with a thickening agent containing polycyanoacrylate prepared by polymerization of a second cyanoacrylate monomer initiated with an aqueous solution of ammonium hydroxide or alcohol. In light of low boiling point of ammonium hydroxide and alcohol, they can be easily removed by heating at low temperature. As such, conventional premature polymerization of adhesive substrate owing to addition of a thickening agent containing residual accelerators can be overall improved.