In order to improve the off-screen distance of holographic optical element integral imaging 3D display, a method to enhance the off-screen distance by using computational-generate holographic wavefront design and modulate the wavefront divergence angle of each imaging pixel is proposed. Through computer simulation of the designed wavefront, 66.0 mm continuous 3D depth of field is obtained. Optical reconstruction experiment based on spatial light modulator achieves 140.0 mm integral imaging off-screen display and 75.0 mm continuous 3D depth of field. This method can provide a good method for holographic optical element integral imaging 3D display to enhance off-screen distance, 3D resolution and 3D depth of field.