The present invention relates to an indicator of a kind of bio-chemical reagents which uses peroxidase as indication system. By 1000 ml of reagent the composition of said indicator contains MOPSO 7.21g, MOPSO sodium salt 4.45g, sodium azide 0.2-1.0g, bovine serum albumin 0.2g, Qulatong-1002 5g, 4-aminoantipyrene 1.0-3.0g, peroxidase 10-30 ku and phenol-formic acid, 1.0-4.0g. By adding high-concentration sodium azide as [O] removing agent the formation speed of red quinoinmine chromopexis can be greatly delayed, the storage time of the reagent can be greatly prolonged. After one year of storage at 2-8 deg.C, the blank absorbancy of the reagent is still below 0.2A, its stabilizing time is above one year.