Abstract: To determine the quality changes and shelf life of grass carp fillets with sizing (GCFS), the aerobic bacterial count, microbial succession, water holding capacity (WHC), total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), biogenic amines, ATP-related compounds and K value of GCFS were analyzed during storage at 4 ℃ and 10 ℃. Results showed that the aerobic bacterial count of GCFS stored at 4 ℃ and 10 ℃ approached or exceeded the limit on 7 d and 3 d, respectively, suggesting that low temperature significantly affects microbial amplification and microflora composition in GCFS, especially retarding the growth of Acinetobacter, Shewanella and Aeromonas. During storage, no significant difference (P>0.05) of WHC in samples was observed. The pH of GCFS reached the lowest level on 3 d, and the contents of TBARS, TVB-N and the specific biogenic amines (cadaverine, putrescine, histamine and tyramine) increased continuously. Furthermore, the changes in nucleotide degradation were greatly affected by storage temperature. The K value of GCFS exceeded the recommended limit value (60%) after 7 d of storage at 4 ℃ or 3 d of storage at 10 ℃, meaning that the samples entered the stale state. The results of sensory evaluation showed a negative correlation between the quality and storage time, with the phenomena of textural softening, flesh discoloration and fishy-smell aggravation in raw/cooked GCFS stored at 10 ℃ for 3 d and 4 ℃ for 5 d. Considering the results of various indicators and the pursuit of high edible quality, the suggested shelf life of GCFS at 4 ℃ and 10 ℃ was 3 d and 1 d, respectively.