Lead zirconate titanium solid-solution (PZT) thin films with various thickness are synthe-sized on titanium substrates by repeated hydrothermal treatments. Young modulus, electric-field-in-duced displacement and the density of the PZT film are measured respectively. Bimorph- type bendingactuators are fabricated using these films. The model, which is used to analyze the driving ability ofbimorph-type bending actuators by hydrothermal method, is set up. It can be seen that the drivingability of bimorph-type bending actuators can be greatly improved by optimizing the thickness of PZTthin film and substrae from the theoretical analysis results. The measured values are expected to agreewith the theoretical values calculated by the above model. Lead zirconate titanium solid-solution (PZT) thin films with various thickness are synthe-sized on titanium substrates by repeated hydrothermal treatments. Bimorph- type bendingactuators are fabricated using these films. The model, which is used to analyze the driving ability of bimorph-type bending actuators by hydrothermal method, is set up. It can be seen that the drivingability of bimorph-type bending actuators can be greatly improved by optimizing the thickness of PZTthin film and substrae from the theoretical analysis results. The measured values ​​are expected to agree with the theoretical values ​​calculated by the above model.