The invention relates to a method for treating the heavy-nitrogen mother solution generated from production of dinitrodiazophenol, comprising the following steps of: collecting the heavy-nitrogen mother solution into a primary acid-base regulation pool, mixing, adjusting the pH value to 3, lifting onto an iron-carbon bed, making the effluent flow into a secondary acid-base regulation pool, adjusting the pH value to 3-4, feeding into a Fenton-like reaction pool for reaction, making the mother solution flow into a neutralization pool, adding carbide slag to adjust the pH to 7-8, filing nitrogen in the mother solution at the same time, making the mother solution flow into a flocculation and sedimentation pool, feeding the supernatant obtained by settling into a subsequent biological treatment unit, treating until the supernatant reaches the standard, discharging or recycling, lifting the sludge obtained by precipitating into a sludge concentration pool, making the supernatant obtained by concentrating reflow into the primary acid-base regulation pool, feeding the concentrated sludge into a horizontal helical centrifuge for centrifugal dehydrating, mixing the dehydrated sludge into steam coal for combustion and utilization, and making a centrifugal separation solution reflow into the primary acid-base regulation pool. The method provided by the invention has the advantages of low investment and stable effect, adopts the carbide slag and waste the scrap iron as the materials for treatment and achieves the purpose of treating the wastes by the wastes.