Objective  To study the standard curve method for determination of superoxide dismutase (SOD) in serum.Method  The principle of catalytic fading reaction was applied to the pyrogallol autoxidation for determination of SOD in serum.The pyrogallol of the reaction concerntration 3?mmol·L    -1   was used for autoxidation 15?min in the pH8.30 KH  2PO  4～Na  2B  4O  7 buffer solution.The logarithm of the ratio(  A    0/  A    S),the absorbance A  0 of the reference tube to the absorbance   A  s of the sample tube at 337?nm was proportional to the concerntrations of SOD.Result  The standard curve equation with the SOD concerntrations range from 2.25 to 27.0?mg·L    -1  (the activity:from 3.25 to 39.00?U·ml    -1  )was obtained as follows:  lg  A    0/  A    S=  -0.007?3+0.012?3  C  ,  r  =0.999?5.The mean recovery of 100%(  s  =3.0%,  n  =24)was found by the presented method.The relative standard deviations within the day and between days were 4.5% and 5.6% respectively.Conclusion  The principle of catalytic fading reaction is successfully applied to the pyrogallol method for determination of SOD in serum.