Abstract: The depth of microcrack was measured by laser scanning confocal microscope (LSCM), which was occurred by intergranular corrosion in 304 stainless steel of different sensitivity condition. The evaluation method of intergranular corrosion sensitivity of the 304 stainless steel was established by analysis the crack depth. It was found that if the intergranular crack depth was larger than 0.5 μm, the intergranular corrosion was believed to happen in 304 stainless steel.