The structural response of piezoelectric thin films to applied electric fields is an important key for understandings the physical properties, more especially the determination of piezoelectric constants. In this context, despite low deformation, structural investigations by X-ray diffraction to obtain a fairly accurate answer represent a great interest (nondestructive, easy to use, and available in most of laboratories). Today, with the widespread use of high-resolution X-ray diffraction technique, the precision needed for such small deformations can be obtained on a conventional laboratory diffractometer and thus used to determine the piezoelectric coefficients in a thin film. This work presents an operating protocol using laboratory HR-XRD technique to determine the effective piezoelectric coefficient in a LaNiO3/BaTiO3/Nb doped SrTiO3-(1 0 0) thin film elaborated by Pulsed Laser Deposition. This one was determined to 50 ± 4 pm V−1. An asymmetry in the structural deformation was observed and discussed by considering the trapping charge in the interface and the clamping effect induced by epitaxial growth. Finally, it has also been shown that the study on the structural deformation monitored in temperature, allows also the determination of phase transition temperature (ferroelectric/paraelectric) in the thin film.