The long-term storage properties of a notric acid ester (OTTO-II) were investigated by elevated-temperature aging test, natural environment storage test, hydrothermal environment metal compatibility (causticity) test. Results show that its safe storage life estimated at 30 ℃ is not less than 11 a and its ingredients unchanged after stored for 2.4 a under the natural environment. The water in OTTO-II is saturation after storied under the hydrothermal environment conditions of 60 ℃, 85%RH, and 30 d, but the content of the stabilizer and notric acid ester is stable. The magnesium flakes in the hydrothermal environmental, machined by 6 different ways, are not corroded by OTTO-II. Only one flake catalyzes the decomposition of PGDN because of unsuitable machining technique for metal surface.