To study the changes of flavor volatiles and the optimal time of chilled storage during postmortem period, cattle rumen and abomasum were studied by gas chromatography-mass spectrometry (GC-MS) at 0, 1 and 3 d. Fuzzy comprehensive method was used to evaluate the quality of rumen and abomasum. The results showed that 79 kinds of volatile flavor compounds were detected in rumen during postmortem period, and 70 kinds of volatile flavor compounds were detected in abomasum. Among them, 1-octene-3-alcohol, isoamyl alcohol, 1-nonyl alcohol, acetic acid, hexanal, isovaleraldehyde, heptaldehyde, benzaldehyde, 3-hydroxy-2-methyl ethyl ketone, methyl disulfide, dimethyltrisulfide, benzothiazole, 2-acetyl thiazole and 2-pentyl furan were the key aroma compounds of rumen and abomasum. And isometric acid, camphoric acid, n-octanal, nonyl aldehyde, phenol and indole were the key flavor substances which affected the quality of rumen and abomasum. Furthermore, the maximum effect on the rumen muscle flavor was 3 d, and wrinkled stomach 0 d. The quality from high to low by fuzzy comprehensive evaluation in rumen was 3, 0 and 5 d, and in abomasum was 0, 3 and 5 d. In summary, the greatest effect of freezing on the flavor quality was 3 days for the rumored muscle and 0 day for the abomasum .