Taking wheat flour as the object, the relationship between grade identification of wheat flour, processing precision and wheat flour color, flour yield was researched by statistical analysis of the classification of wheat flour, bran speck, compared with wheat flour color control material standard sample. The results showed that the average flour yield of the 241 wheat samples was 61.4%, with the maximum of 68.9%，and the minimum of 50.1%; the average whiteness was 76.9. There was an incompletely negative correlation between flour yield and whiteness value, which indicated that wheat flour color had a great relationship with wheat variety.