Abstract: Metmyoglobin and a value were studied by analyzing changes of the texture, a value, metmyoglobin and TBA value of crisp grass carp fillet during refrigeration process.The result showed that a and myoglobin content gradually decreased with refrigerated time prolonging, whereas metmyoglobin content increased with the extension of the refrigerated time.Moreover, that negative correlation between a and metmyoglobin content or TBA value was significant.It found that carnosine, ascorbic acid and niacinamide vailed affected significantly the colour of red muscle in the fillets by the D-optimal design test.Carnosine, ascorbic acid and niacinamide vailed reducing discoloration in red muscle of crisp grass carp fillet, especially carnosine.The optimal concentration of carnosine, ascorbic acid and niacinamide were 8mmol/L, 0.04% and 0.02%, respectively.The result further revealed that a correlated negatively to content of metmyoglobin, and a values could be used to quantify the changes of colour in the red muscle of crisp grass carp during refrigeration process.