To resolve mutual restriction of viewing angle and optical efficiency, an integral imaging (II) 3D displayer based on a variable-aperture pinhole array was proposed. The imaging model of the II 3D displayer based on the variable-aperture pinhole array was established. The calculation formulas of the viewing angle and optical efficiency were obtained by using geometrical optics. How to adjust the viewing angle and optical efficiency by changing the aperture width of the pinhole was illustrated in detail. A prototype of the II displayer based on the variable-aperture pinhole array was developed. The variable-aperture pinhole array was electrically controlled by using a liquid crystal display screen. The experimental results prove that the viewing angle and optical efficiency of the 3D image were respectively enhanced by increasing and decreasing the aperture width of pinhole.