The invention discloses a method of preparing sample wafer capable of representing the grain sliding of steel and iron materials, and belongs to the technical field of corrosion of steel and iron materials. The process steps and control technical parameters are as follows: carrying out solution annealing on metal materials in a heating furnace at a temperature of 1050 DEG C for 30min, and cooling by means of water cooling; carrying out cold-machining material cold deformation by using a micro-type rolling mill in a machining workshop under the conditions of a pass number of 5, a thickness reduction of 20% every time, a room temperature and a unidirection; sensitizing at a temperature of 650 DEG C for 24h, and cooling with the furnace; and carrying out scratch treatment, namely preparing scratch lines slantwise penetrating through grains on the surface of a test sample, in this way, after stretching in a high-temperature furnace, representing the grain sliding by the scratch lines, so as to obtain the sample wafer enabling stress corrosion cracking to be observed under SEM. The method has the advantage of qualitatively obtaining the inhibition effect of two-phase grains on the prevention of the stress corrosion cracking.