Multilayer films can achieve advanced properties and a wide range of applications. The heterogeneous interface plays an important role in the performances of multilayer films. In this paper, the effects of the interface of Ba(Mg1/3Ta2/3)O3/PbZr0.52Ti0.48O3 (BMT/PZT) thin films on dielectric behavior and temperature stability are investigated. The heterogeneous interface structures are characterized by Auger electron spectroscopy (AES). The PZT-BMT interface is different from the BMT-PZT interface in thickness. For the PZT-BMT interface, the PZT thin films are diffused to the whole BMT layers, and the interface thickness is about 90 nm, while the BMT-PZT interface’s thickness is only about 8.6 nm. The presence of heterogeneous interfaces can improve the performances of BMT/PZT thin films and expand their applications. The dielectric constant of BBPP thin films is significantly lower than BPBP thin films, while the dielectric loss is exactly the opposite. The more interfaces there are, the greater the dielectric constant. The relationship between the electric-field-dependent dielectric constant curve and the P-E curve is established. The equivalent interface barrier of the diode is used to show that the dielectric peaks under the positive and negative voltage are different. Similarly, heterogeneous interfaces show a certain improvement in dielectric tunability and temperature stability.