To improve its dimensional stability, the microstructure and residual stress of hot isostatically-pressed beryllium were regulated by low-temperature aging. Results show that after low-temperature aging, the dimensional shrinkages of hot isostatically-pressed beryllium, annealed beryllium, and thermal-cold cycled beryllium are evidently reduced. Various stabilizing mechanisms, including dislocation homogenization and coordinated grain micro-deformation, are observed during low-temperature aging, which effectively improve the dimensional stability of hot isostatically-pressed beryllium.