Abstract: Influenced by the earth magnetic field, orientation of the domain organization and irreversible reorientation will occur in internal organization of the loaded ferromagnetic material. The effects of stress on the domains of silicon steel sheet and 20# steel, which were loaded on the different load, the domains were observed with the Bitter method. The results showed that the silicon steel and 20# steel with the low load or no load, there mainly existed 180° domains, dendritic domains, gladiate domains whose walls were parallel with each other in a same crystalline grain, then, with the load enhancing, the domain walls length and space changed and there exited mazy Ⅰ domains and mazy Ⅱ domains, and the number of the mazy domains increased with the load increasing.