Abstract: Correlation of the expression with meat quality had been investigated.Relative quantization PCR was used to evaluate the expression of CAST in 40 Sunit sheep of different month ages. The shear force,p H,color were measured after being slaughtered.The correlation between the expression and the quality of meat were analyzed.The results showed that the expression pattern of CAST gene were same in three muscles in Sunit sheep,the expression of 5,6,8 mouth ages were rising and it was lowest in 12 month age.The expression in 4 month age was:triceps > biceps femoris > longissimus dorsi. The expression was nearly same in biceps femoris and longissimus dorsi in 5 month age.The expression was nearly same in triceps and biceps femoris in 8 month age.The expression in triceps was higher than longissimus dorsi significantly in 8 and 12 month age. The expression of CAST gene in longissimus dorsi had negative correlation with shear force( r =-0.449),yellowness( r =-0.753),p H2( r =-0.245),had significant negative correlation with redness-0.950( p = 0.050),had positive correlation with lightness( r =0.171),p H1( r = 0.387).The expression of CAST gene in biceps femoris had positive correlation with shear force( r = 0.520),yellowness( r = 0.846),had negative correlation with redness( r =-0.091),lightness( r =-0.193),p H1( r =-0.446),p H2( r =-0.446).The expression of CAST gene in triceps had positive correlation with shear force( r = 0.333) and negative correlation with redness,yellowness,lightness,p H1 and p H2,the correlation coefficients were-0.494,-0.465,-0.317,-0.814,-0.629 respectively.