The aim of this study was to explore the changes of flavor quality in lamb during rigor moris and post-rigor periods at 4 ℃. Longissimus dorsi muscle was selected, ultra-rapid gas phase electronic nose instrument and gas chromatography mass spectrometry (GC-MS) were used to determine the difference of volatile flavor compounds among different storage time of lambs. The results showed that 51 kinds of volatile flavor compounds were detected, mainly include aldehyde and alcohol. The aldehyde content of chilled lamb increased first and then decreased with the prolongation of storage time, while the alcohol content first decreased and then increased. Hexaldehyde, heptanal, octanal, nonaldehyde, 1-pentanol, 1-octene-3-alcohol and 1-heptanol were the key flavor compounds as these compounds always existed in lamb during storage. The difference was not significant in the key flavor compounds between 1 d and 1 h of lamb after slaughtered (p>0.05), however, the kinds and contents of flavor compounds in 3 d and 5 d of lamb decreased. The results of principal component analysis carried out by ultra-rapid gas phase electron nose were consistent with the GC-MS. Therefore, there was no significant difference in the types and contents of the key flavor compounds between pre-rigor (1 h after slaughtered) and the initial stage of rigor (1 d after slaughtered), while decreased at post-rigor stage (3 d and 5 d after slaughtered) significantly.