Abstract: In order to evaluate the ferrite content in stainless steel more scientifically and effectively guide the production and product development, the ferrite content in stainless steel was determined by magnetic method, metallographic method and chemical analysis method for different grades of stainless steel products. The results show that the magnetic method was convenient and quick, but it had certain limitations and could not judge the microstructure of stainless steel. The metallographic method could judge the microstructure type of stainless steel, which was divided into serious field-of-view method and average field of view method. The measurement process was more intuitive and reliable. The chemical analysis method could determine the microstructure type and ferrite content of steel, and it was only suitable for qualitative reference.