Abstract: The interaction of the ferroelectric coatings and stress/strain, electric and temperature fields was mathematically formulated with the novel domain-switching model in which the domain switching is activated by the free energy between domain states and based on the expanded micro-mechanical model, theoretically analyzed and numerically simulated to understand its non-linear behavior.Moreover, to differentiate the film from the bulk ferroelectric materials in the coupled thermo-electro-force fields, the remnant strain was considered.The simulated results show that the temperature, electric and strain/stress fields all have a major impact.To be specific, as the temperature increases, the domain becomes less stable and switches easier because of the increasing free energy; an increase of the strain decreases the free energy and makes it more difficult to switch the domains.The simulated results agreed fairly well with the experimental and simulated results reported in literature.