The invention discloses a casting-polarization preparation method for a flexible ferroelectric composite film, and belongs to the technical field of functional conversion material preparation. A static electricity action mechanism which is in the presence when a hydrogen bond is formed is used for inducing a PVDF (Polyvinylidene Fluoride) based polymer molecule to realize layer-by-layer static electricity self-assembling on a casting substrate; in a self-assembling process, dipoles in the ferroelectric polymer are arranged in order to realize in situ self-polarization; then, a polarized dopingceramic phase is subjected to thermal poling processing, so that the ferroelectric polymer phase and a ferroelectric doping phase are subjected to same-direction or reverse polarization, and therefore, the interference of a piezoelectric signal in a pyroelectricity application field and the interference of a pyroelectricity signal in a piezoelectric application field can be respectively realized.According to the casting-polarization preparation method provided by the invention, polarizing processing does not need to be carried out in two times, an electric field direction can be regulated according to practical requirements after casting and film formation to polarize the ferroelectric doping phase in one step. Production processes are simplified, equipment input is reduced, and the casting-polarization preparation method has the advantages of low cost, high reliability and smaller energy consumption and is very favorable for advancing the industrialized production of the flexible ferroelectric polymer film.