Ammonium dinitramide （ADN）， as a high-energy green oxidizer， faces significant challenges in engineering applications within solid propellants due to its high surface polarity and strong hygroscopicity. To improve the hygroscopicity of ADN， both emulsion and liquid-phase methods were employed to graft hydrophobic amine compounds， oleylamine and 4-fluorobenzylamine， onto the surface of spherical ADN （PADN）， thereby preparing the modified spherical ADN（PMADN）. The structure and properties of the modified ADN were characterized using scanning electron microscopy-energy dispersive spectroscopy （SEM-EDS）， thermogravimetric-differential thermal analysis （TG-DTA）， and X-ray photoelectron spectroscopy （XPS）. Additionally， hygroscopicity studies were conducted using the desiccator equilibrium method. The results confirmed both amine compounds were grafted successfully and the spherical morphology of the modified ADN was intact. The thermal decomposition temperature of the modified ADN increased from 196.3 ℃ （raw ADN） to 198.3 ℃ and 200.7 ℃， and the impact sensitivity improved from 17.95 J to 24.35 J and 28.80 J （average value）， respectively. After 144 h under 25 ℃ and 57% relative humidity， the moisture rates of the two modified spherical ADN were 1.37% and 1.07%， decreasing 74.95% and 80.44% compared to that of the raw ADN. Additionally， no caking or liquid water was observed on the surface， indicating the modified ADN had excellent anti-hygroscopic properties.