Objective To investigate the structure type, formation process and applications of 304 stainless steel after chemical etching. Methods The etching rule of 304 stainless steel was found by chemical etching in etching agent of FeCl3 solutions. The types of the surface structure and the forming process were studied by surface analysis and SEM. Results The law was in line with the following equation about the hydrochloric acid dosage (y) to smoothen the surface of 304 stainless steel along with the changes in nitric acid concentration(x): y=19. 37+0. 13x±0. 5, x≤120 mL/ L; y = -8. 67+0. 62x±0. 5, x≥130 mL/ L. The content of Cl- in etching solution was the major influencing factor for the surface roughness of the stainless steel after etching. Conclusion Changing the solution property could alter the surface structure of 304 stainless steel after etching.