Abstract: Whole grain products have good prospects as consumers become more aware of scientific eating. However, there are few researches on the effect of water content on the flavor of whole wheat food. Therefore, this study aimed to explore the influence of different moisture content of bran embryo after extrusion on the key flavor substances of whole wheat noodles. In this study, whole wheat noodles with different water content were prepared by extrusion stabilization of wheat bran and backfilling. The volatile flavor compounds in whole wheat noodles were analyzed by solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) technique, and the relative odor activity (ROAV) method combined with principal component analysis (PCA)was used to determine the characteristic flavor compounds in whole wheat noodles, as well as the influence of wheat bran and embryo with different water content on the contribution of specific flavor compounds. The results showed that the changes in water content of wheat bran and embryo had significant effects on the volatile compounds of whole wheat noodles, especially aldehydes and esters. The flavor contribution of n-hexanal, heptanal, nonanal, decanal, diiso-butyl phthalate and 2-n-pentyl furan increased firstly and then decreased, while the flavor contribution of n-octanal decreased gradually with the increase of water content.(Z)-2, 4-sebacdienal appeared when water content was 25% and its flavor contribution reached the maximum value of 100, which had a very significant effect on the flavor of whole wheat noodles.(E)-2-nonenal appeared when the water content was 13%, 17% and 21%, and the flavor contribution reached a maximum of 100. In cooked-whole wheat noodles, with the increase of water content, the overall flavor contribution of nonanol decreased.The flavor contribution of (E)-2-nonenal and 2, 4-nonadienal did not change significantly; 2, 4-sebacdienal had a certain effect on the flavor of whole wheat noodles when the water content was 13% and 21%. (Z)-2, 4-decdienal had a maximum flavor contribution of 100 at the moisture content of 13%, 17%, 21% and 25%, so it was the main flavor source of cooked whole-wheat noodles. The ROAV value of raw whole-wheat noodles showed that n-hexanal, n-octanal, nonanal, and decanal contributed more to the flavor of whole-wheat noodles, while in cooked-whole wheat noodles were trans-2, 4-decadienal, cis-2-nonanal and 2, 4-nonadienal. These seven substances endowed whole wheat noodles grass flavor, fruit flavor, fat flavor, meat flavor, and other main flavors.