The invention provides a dendritic crystal corrosive of heat-resistant steel containing chromium, and a display method. The display method comprises steps, such as performing mechanical grinding for aheat-resistant steel metallographic specimen, mechanical polishing, dendritic crystal corrosion, washing and baking to dry and observing with a microscope. The metallographic corrosive provided by the invention is mixed solution of saturated picric acid water solution and ferric chloride solvent, and the metallographic corrosive is prepared through preparing totally 100ml of mixed solution of thesaturated picric acid water solution and 20%-30% by mass of ferric chloride solvent according to volume ratio of 10:1, and further adding sodium dodecyl benzene sulfonate. With the dendritic crystaltissue display method provided by the invention can clearly display dendritic crystal tissue of the heat-resistant steel metallographic specimen containing 9% of chromium, and consequently, is beneficial for measurement of growth length of the dendritic crystal.