Two-dimensional (2D) ferroelectric materials with robust polarization down to atomic thicknesses provide novel building blocks for functional heterostructures. The effects of ferroelectric polarization on the electronic properties of 2D ferroelectric heterostructures are rarely investigated. Here, based on the first-principles calculations, we study the effect of ferroelectric polarization and interlayer coupling on the electronic properties of the 2D In₂Se₃/InSe ferroelectric heterostructure. It is found that the ferroelectric polarization of In₂Se₃ can effectively tune the band alignments of the In₂Se₃/InSe heterostructure. When the direction of ferroelectric polarization is reversed (i.e., from up to down), the band alignments of In₂Se₃/InSe heterostructures transition from type I to type II. Meanwhile, we find that the transition between type I and type II band alignments can be induced by means of interlayer coupling (i.e., varying interlayer distances). The results demonstrate that ferroelectric polarization and interlayer coupling are effective methods to modulate the band alignments of In₂Se₃/InSe heterostructures.