Ferroelectric superlattice are artificial film materials with layered periodic structure formed by the alternate growth of two or more ferroelectric materials or non-ferroelectric materials at the unit cell scale. Ferroelectric superlattices can exhibit excellent ferroelectric, piezoelectric, dielectric and pyroelectric properties due to the existence of a large number of heterogeneous interfaces and the remarkable interface effect, and even show new functional properties that are not available in their constituent materials. Therefore, ferroelectric superlattices not only provide an ideal platform for studying the interaction between charges and lattices at the interface of complex oxide materials, but also play an indispensable role in the next generation of integrated ferroelectric devices. With the development of preparation and characterization methods, researchers can design and control the microstructure and chemical composition of ferroelectric superlattice at the atomic scale to improve the functional properties of ferroelectric superlattice thin films. Ferroelectric polarization is the most basic property of ferroelectric film materials. In addition to being used for information storage devices, ferroelectric polarization also plays an important role in regulating the energy conversion performance of integrated ferroelectric devices such as piezoelectric devices, photovoltaic devices and electrocaloric devices. Therefore, the ferroelectric polarization intensity of ferroelectric superlattices directly determines the functional characteristics