Using the modified transverse Ising model, and the effective field theory based on the probability distribution technique, the phase transition temperature, the polarization and susceptibility for ferroelectric thin films with structural defects are studied. It is shown that the defect layers in ferroelectric thin films can induce strong increase or decrease of the critical temperature of ferroelectric phase transition due to different exchange interactions in the defect layers. The obtained results are in qualitative agreement with experimental data for thin ferroelectric film with different thickness.