The influence of lateral mechanical stresses on the crystal structure, microstructure and dielectric properties of spherulitic thin films of lead zirconate titanate is studied. The composition of lead zirconate titanate corresponded to the region of the morphotropic phase boundary. In thin films, the perovskite phase was formed during high-temperature annealing of amorphous films deposited by RF magnetron sputtering of a ceramic target on a cold silicon substrate. The deformation of the crystal lattice caused by the change in density during crystallization of the perovskite phase in the films changed with an increase in the area of spherulitic blocks with a variation in the target-substrate distance during their deposition. An increase in mechanical stress led to a linear rotation of the crystal lattice and a change in its parameters, as well as to a change in the microstructure of thin films. Based on the temperature dependences of the reverse dielectric permittivity, changes in the temperature of structural phase transitions in the films were revealed.