Compared to conventional silicon-based electronics, flexible electronic devices have been extensively studied for their unique advantages of distinguished portability, conformal contact characteristics, and human-friendly interfaces. As an important branch of flexible electronics, flexible memory has shown good application prospects in wearable devices, smart medical care, electronic skin and other fields. At the same time, with the in-depth application of 5G, artificial intelligence, the internet of things and other new generation of information technologies, the market demand for high density, non volatile, ultra-low power consumption of flexible memory continues to release, giving birth to the research boom of flexible ferroelectric memory devices. Herein, the preparation of flexible ferroelectric films and the progress of their application in memory field are reviewed. Prevailing methods for preparing flexible ferroelectric films including the van der Waals heteroepitaxy on flexible substrate, delamination of the ferroelectric films on rigid substrate by chemical etching techniques, and growth of novel 2D ferroelectric materials are summarized. The research progress of flexible ferroelectric devices applied to memories are also be discussed. Finally, the challenges and prospects of flexible ferroelectric devices in the future are briefly proposed.