Three kinds of domestic summer grains, barley, naked-barley & wheat were used for the assessment of ash, protein, fat, crude fiber, calcium, iron & thiamine contents in the grain-pearling and flour-milling processes at the 60%, 70%, 80%, 90% yield bases and the following results were obtained. 1) Ash, protein, fat, crude fiber, calcium, iron & thiamine contents of milled grains were proportional to the milling yield in grain-pearling and flour-milling processes. 2) In the case of pearled barley, the average content of ash was 0.83%, protein was 1.31%, fat was 0.40%, crude fiber was 0.75%, calcium was 3.03mg%, iron was 2.40mg% and thiamine was 0.14% lower than the barley flour at the same level of milling yield. 3) In the case of pearled naked-barley, the average content of ash was 0.41%, protein was 1.96%, fat was is 0.33%, crude fiber was 0.84%, calcium was 4.54mg%, iron was 1.19mg% and thiamine was 0.10mg% lower than the naked-barley flour at the same level of milling yield. 4) In the case of pearled wheat, the average content of ash was 0.28%, protein was 2.25%, fat was 0.05%, crude fiber was 0.25%, calcium was 4.31mg%, iron was 0.12mg% and thiamine was 0.15mg% higher than the wheat flour at the same level of milling yield.