The invention discloses a high-density nondestructive reading ferroelectric domain wall memory. The nano-ferroelectric domain wall memory comprises a single crystal substrate layer, a bottom electrodelayer and a ferroelectric material layer in sequence from bottom to top, wherein the ferroelectric material layer is composed of a plurality of square blocks arranged at equal intervals. Square ferroelectric units with the side length being less than 600 nanometers are obtained through controlling different growth conditions, the process is simple and effective, and the damage caused by photoetching and etching with high cost and complicated process to the material performance. The ferroelectric domain wall device unit prepared according to the invention forms topological protection for the ferroelectric domain wall by using shape geometry boundary conditions so as to realize the voltage-controlled non-volatile conductive domain wall which is high in switching ratio, stable and capable ofbeing repeatedly erasable. The ferroelectric domain wall memory realizes information storage taking the ferroelectric domain wall with high density and low power consumption as the unit by effectively utilizing the characteristics of small size and low control voltage of the ferroelectric domain wall.