Abstract:The change rules of pH value，juice loss rate，color difference，total volatile basic nitrogen value（TVB-N），thiobarbituric acid value（TBA），and total bacterial count during storage of refrigerated grass carp were studied，and the relationship between each index was also discussed.The grass carp was cut into segments and packed in germicidal packaging，and the above indexes were measured every 24 h.The results showed that the grass carp at 4℃ was stored for 10 days，pH value and volatile based nitrogen were presented linear variation，every 24 h measured pH value and volatile salt based nitrogen a positive correlation（P<0.01）and was more objective and accurate，its fitting regression equation：Y=33.833X-220.44 （P＜0.01），the coefficient of determination was 0.978 2.The pH determination of grass carp pH value can be calculated TVB-N value，determine the freshness of grass carp on the simple and rapid objective.This model can be used to determine the freshness of grass carp more quickly.