It is well known that Poly (vinylidene fluoride) (PVDF) and the family of P(VDF-TrFE) [TrFE = trifluoroethylene] copolymers are crucial candidates for high-performance piezoelectric devices. In this research article, a series of PVDF-TrFE/ZnO thin films were prepared by means of spin-coating method. Different parameters of this process such as the speed of spin-coating and temperature of annealing were discussed. In order to investigate the effect of these parameters on the ferroelectric phase of samples, various characterizations such as SEM, FTIR, XRD and DSC were utilized. Results revealed that annealing temperature played a significant role in the crystallinity of those thin films, the transformation of ferroelectric phase and the perfection degree of crystallization. Besides, with in a certain range, the lower speed of spin-coating favors better formation of ferroelectric phase.