Abstract: In order to study the feasibility that laser technology was used to distinguish different metallographic structures, two different metallographic structures of pearlite + ferrite and martensite were obtained by different heat treatment methods. The suitable laser pulse energy was chosen, and the relationship between breakdown spectral line strength induced by laser and metallographic group was analyzed and compared. The principal component analysis was used to distinguish the different metallographic structures. The experimental results show that the spectral line intensity of different metallographic structures is different. The spectral line intensity of pearlite + ferrite structure is larger. The difference of spectral line strength with matrix element Fe is larger than that with matrix element alloy Mn. Different metallographic structures show certain distribution characteristics. Principal component analysis method can distinguish the different metallographic structures. The distinguishing result is the best in wavelength range of 280nm~320nm. This study proves that laser technology has the ability to distinguish different metallographic structures.