用热力学唯象埋论研究了二维应力对PbTiO3多晶铁电薄膜相转变的影响。理论分析表明，在二维应力的作用下，薄膜的相转变温度Tc将发生移动，该移动量△T的大小和正负不仅与应力的性质有关，而且与晶粒的取向有关。经推导给出了△T与晶粒取向之间的关系式。对晶粒呈随机取向的多晶薄膜，在二维张应力的作用下，平均Tc将向高温移动，并且相转变温区将展宽。 The effect of two-dimensional stress on the phase transition of PbTiO3 polycrystalline ferroelectric thin films was investigated by thermography phenomenology. Theoretical analysis shows that under the action of two-dimensional stress, the phase transition temperature Tc of the film will move. The magnitude and positive and negative of the moving amount ΔT are not only related to the nature of stress but also to the orientation of the grains. The relationship between △ T and grain orientation is derived. For a polycrystalline film with randomly oriented grains, under the action of two-dimensional tensile stress, the average Tc will move towards high temperature and the phase transition temperature will broaden.