OSL fading with storage time after irradiation remains a major obstacle in the development of ideal OSL materials. Dy and Eu co-doped NaMgF3 are attractive candidates for various rare earth doped matrix materials. In this study, NaMgF3:Dy,Eu was synthesized by a solid-state reaction, and the effects of heating temperature, duration, atmosphere, and cooling rate on XRD, TL and OSL properties were studied. A simple, safe, efficient, and time-saving solid-state reaction was identified as a potential method for the preparation of NaMgF3:Dy,Eu, which could be optimally prepared by heating at 750 °C for 2 h under nitrogen atmosphere (2 l/min) followed by rapid cooling. The results show that NaMgF3:Dy,Eu has a more stable OSL response and an excellent TL glow curve, with only a 0.4% decrease in the OSL signal read after 1 d of dose irradiation compared to that immediately after irradiation, and a high main TL peak at ∼320 °C. It has been indicated the OSL signal in this material seems to be strongly related to the main TL peak. The material has a considerable OSL sensitivity and decay rate than the Luxel Detector. NaMgF3:Dy,Eu will have a promising future in the field of OSL dosimetry due to its near tissue equivalence, low OSL fading without preheating, fast OSL decay rate, and predictable and easily reusable dose elimination.