In some reactors, ammonia and its radiolytic product (H₂) are used to scavenge the oxidizing species (H₂O₂, O₂, and ?OH). A reducing chemical environment is thus created and the pH of the coolant is regulated simultaneously. In the present study, the radiolytic behaviors of deoxygenated ammonia solution were studied in the γ-ray field. The impacts of N₂ pressure, gas-liquid volume ratio, and temperature on deoxygenated ammonia solution radiolysis were investigated. The pH and the concentrations of residual ammonia, H₂, and nitrogen oxides (NO₂^- and NO₃^-) were analyzed. The results revealed that the variation of N₂ pressure (0.5~5.0 MPa) and gas-liquid volume ratio had no influence on the concentrations of residual ammonia and nitrogen oxides. NO₂^- and NO₃^- concentrations were approximately 1 mg/L at room temperature when the absorbed dose was 28.8 kGy. However, the apparent concentration of H₂ significantly decreased with the N₂ pressure and gas-liquid volume ratio. The loss fraction of ammonia considerably declined from 26.5% to 8.4% when the temperature increased from 25 to 200 ℃, demonstrating that the radiolysis of ammonia was suppressed at the elevated temperature. However, the concentrations of NO₂^- and NO₃^- increased to 34 and 3 times, respectively, at 200 ℃ compared to those at 25 ℃. In addition, a radiolysis model of ammonia-containing coolant was established in the present study. The maximum relative error between experimental data and calculation results at any temperature was 4.1%. The model was thereafter used to calculate residual ammonia concentration with the absorbed dose under different initial ammonia concentrations. The results revealed that it was necessary to replenish ammonia regularly when using it alone to inhibit oxidizing species.