The invention discloses a gold phase corrosive and a gold phase displaying method for displaying a crack microscopic structure. The gold phase corrosive is prepared from the following components: 5 to 6 percent by mass of bitter acid, 0.1 to 0.3 percent by volume of ferric chloride solution, 4 to 5 percent by mass of an anionic surfactant and 2 to 4 percent by volume of nitric acid. The gold phase corrosive disclosed by the invention is suitable for observing cracks in steel and iron materials, and the microscopic structures of the steel and iron materials are martensite, bainite and sorbite. By adopting the gold phase displaying method disclosed by the invention, the microscopic structure around the cracks can be obviously distinguished, and the judgment on crack defect reasons can be facilitated.