Abstract: The digital photomicrography method of metallurgical microscope is validated,according to the ISO/IEC 17025:2005,in which the new system is installed in the Neophot32 microscope. The specimens are 0.01 mm micrometer,ductile iron and designed graphics. The validation comprises tractability of a quantity value,definition,magnification,field of vision,length measuring,image comparing,and area ratio measuring. The microstructure is in focus,magnification is precision,and visual field measures meet responsive standard. The magnification can trace to SI. Using the image analyze software,the result sequal to or better than that responsive standard method. As a result,the digital photomicrography system can satisfy requirements of microstructure analyze and test,and replace the old film photomicrography system.