The present invention relates to a method for detecting and quantifying a target substance using a biochip having a substrate onto which probe molecules are fixed, and more particularly, to a method for detecting and quantifying a target substance with the naked eye by using a biochip, comprising the steps of preparing a biochip having a substrate onto which probe molecules are fixed, contacting the biochip with a sample containing a target substance having electric charges, reacting the target substance with nanoparticles having electric charges that are opposite to those of the target substance, and then reacting with a metal enhancing solution so as to amplify the size of the nanoparticles.