Before being exported to select overseas markets, Thai mangoes must be treated with ionizing radiations as a phytosanitary treatment. Irradiated mangoes, on the other hand, used to have a number of issues when they reached their destinations, including interaction with postharvest diseases and rotting during transportation. Exporters suffer significant losses as a result of this. The goal of this project was to predict mango fruit maturity from near-infrared spectroscopy technology (NIR) combining postharvest processing with irradiation. Using an NIR spectrometer, we determined the total soluble solid (TSS) of mangoes. After that, those mangoes were submerged in hot water containing 500-ppm systemic fungicide solution. 'Nam Doc Mai Si Thong', 'Nam Doc Mai No.4', and 'Khieo Sawoei' were the three kinds of fresh mangoes we used. At a generic phytosanitary dose of 400 Gray, those mangoes were irradiated with gamma (1.25 MeV) and x-ray (5 MeV) radiation. The irradiated mangoes were subsequently kept at 13–15 °C for 12 days, with disease incidence being monitored every three days. We discovered that NIR had the best predicted R2 value of 0.96 at 80 percent maturity (7–13 percent Brix). During 12 days of storage, a mixture of hot water and systemic fungicide helped keep disease incidence in non-irradiated mangoes below 6%, but no disease was found in irradiated mangoes. Irradiation reduced respiration rate and ethylene production, slowed the formation of TSS and titratable acidity ratios, and as a result, it extended the shelf life by at least 12 days. Mangoes can be treated using irradiation, excellent postharvest procedures, NIR, and dipping in hot water mixed with systemic fungicide solution to keep their quality and shelf life.