Herein， we develop a new method to prepare the ammonium dinitramide/pyrazine-1， 4-dioxide （ADN/PDO） cocrystal， which is highly efficient and environmental-friendly due to utilizing the reaction crystallization with pure water as the solvent， and also comprehensively characterized its performance. The morphology and structure of the cocrystal were characterized by optical microscopy （OP）， powder X-ray diffraction （PXRD）， and single crystal X-ray diffraction （SXRD）， respectively. In detail， the ADN/PDO cocrystal was prismatic and formed by the combination of ADN and PDO molecules at a molar ratio of 2∶1. Moreover， the ADN/PDO cocrystal belongs to the monoclinic crystal system with a space group of P2₁/c， owning a theoretical density of 1.779 g·cm^-3 at room temperature. Furthermore， through the differential scanning calorimetric （DSC） measurement， it turned out that the melting point of the prepared ADN/PDO cocrystal is 113.3 ℃， which is 21.3 ℃ higher than that of ADN， and the decomposition temperature is slightly higher than that of ADN， demonstrating good thermal stability of the prepared ADN/PDO cocrystal. Then， the hygroscopicity of the prepared cocrystal， measured by the weight increment method， is significantly low at only 2.6%， while that of ADN is at 45%. In addition， calculated by the NASA CEA， the theoretical specific impulse of the cocrystal reaches 277.9 s while that of ADN is 197.5 s， demonstrating the high energy performance of the cocrystal. In conclusion， the reported method based on the reaction crystallization successfully enables the efficient production of a high-energy， low-hygroscopic ADN/PDO cocrystal， thereby facilitating the further assessment of its application performance.