Abstract: Ferroelectric memory exhibiting excellent performance has attracted many attentions for its low power consumption, high endurance and non-volatile storage capability.Storage of a large amount of data requires high-density integration of memory devices, and the storage medium is getting thinner.However, the ferroelectric properties of conventional perovskite materials degrade if the storage medium is very thin, which is a great challenge to integrate storage device in high-density.Hafnium oxide in an orthorhombic (Pca2₁) phase exhibits ferroelectric properties that is well kept even if the thickness of hafnium oxide is 1 nm.Additionally, it is well compatible with CMOS fabrication processing, which facilitates large-scale integration of ferroelectric memory.Reliability, imprint and wake-up effects are problems of a hafnium oxide based ferroelectric memory, which are closely associated with crystal phases and status of oxygen vacancies.Therefore, this article introduces progress in hafnium oxide memory from doping, effects of mechanical stress and the modulation of oxygen vacancies.