The microstructure of the electrolyte layer in electrochemical actuators significantly influences ion storage and transport, mechanical properties, and the final actuator deformation performance. In this study, two types of polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) electrolyte films with varying fiber diameters were prepared by electrospinning for electrochemical actuators. We controlled the diameters of the fibers by adjusting the concentrations of the polymer solution, while the film is carefully controlled to a consistent size in length, width, and thickness. Subsequently, the fiber film was immersed in the ionic liquid to achieve excellent electrolyte film performance. A poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) electrode thin film was prepared using a drop coating method. Finally, an electrochemical actuator was prepared by hot pressing the electrode and electrolyte films. Compared with the drop-coated electrolyte film, the electrospun counterparts exhibit an excellent flexibility and a porous structure. Among them, the film with a larger fiber diameter (PVDF-HFP 22% (w)) reveals better tensile stress (7.52 MPa), tensile strain (235%), porosity (74%) and surface capacitance (39.8 mF•cm^-2), and its tip displacement is 9.6 mm at ±0.5 V and 0.1 Hz, which is 1.48 times that of the smaller fiber diameter sample (PVDF-HFP 16% (w)) and 3.69 times that of the drop-coated sample, respectively. When at ±2 V and 0.1 Hz, the displacement is as high as 24.3 mm, which is 1.19 times that of the smaller fiber diameter sample (PVDF-HFP 16% (w)) and 1.46 times that of the drop-coated sample, respectively. Under the driving voltage of ±0.5 V and 0.1 Hz, after 10000 cycles, the driving displacement of PVDF-HFP 22% (w) electrochemical actuator can still reach 98% compared with the initial state. By improving the microstructures of electrolyte films through electrospinning, we successfully realized the preparation of high-performance electrochemical actuators, which provides a new idea for the development of soft robots in the future.