In order to clarify the effects of protein oxidation on the quality of longissimus dorsi muscles from Qinchuan beef during chilled storage at 4 ℃， the contents of carbonyl and sulfhydryl groups， pH value， meat color， shear force， purge loss， centrifugal loss and moisture content were measured at different storage periods (0， 2， 4， 6 and 8 d). The results showed that with the increase of time storage， the content of carbonyl gradually increased， and the content of thiol gradually decreased. Muscle pH and centrifugal loss decreased from 0 d to 4 d and increased after 4 d. Purge loss increased gradually with increasing time postmortem. The value of L increased from 0 d to 4 d and then decreased after 4 d， the value of b gradually increased from 0 d to 8 d， and the value of a decreased with increasing time postmortem. The shear force increased before 4 d and then decreased after 4 d. With prolonging of time storage， the bound water (P2b) and the immobilized (P21) water decreased， while the content of the free water (P22) increased significantly. The results of Pearson correlation analysis showed that the content of carbonyl groups were significant negatively correlated with muscle pH， the value of a and the shear force (P<0.01)， and significant positively correlated with the value of b， the purge loss and the centrifugal loss (P<0.01). The content of sulfhydryl groups were significant positively correlated with muscle pH， the value of a and the shear force， and negatively correlated with the value of L， the value of b， the purge loss and the centrifugal loss (P<0.01). The results of this study provide theoretical guidance for the quality control of chilled beef.