The work aims to study the influence of structural parameters of piezoelectric actuator on its driving performance, and optimize its structure, so as to lay a foundation for further research on the jet characteristics of piezoelectric inkjet. The research status of piezoelectric inkjet printing technology in recent years was summarized. The numerical model of piezoelectric actuator was established by finite element numerical simulation software Comsol Multiphysics. The influence rule of structure size of PZT, SiO2 vibrating plate and Parylene protective layer on the displacement of piezoelectric actuator was analyzed. The optimal size of the main components of the piezoelectric actuator was determined by orthogonal test. The structure size of the piezoelectric actuator had great influence on its amplitude, and the displacement of the actuator could be obtained by different structure combinations. The displacement of the actuator reached the maximum when the ratio of the width of the piezoelectric film to the vibration plate was 0.7, the width of the vibration plate was 140 μm, the thickness of the protective layer was 0.7 μm, the thickness of the vibration plate was 0.9 μm, and the thickness of the piezoelectric film was 1 μm. By optimizing the structure size of the piezoelectric actuator, the displacement of the actuator can be maximized, so that its driving performance can be optimized.