The periodic hole array is fabricated on GaAs substrate by holographic lithography and wet etching. The double exposure in holographic lithography is adopted with optimized exposure time of 60 s. Wet etching solution with 1∶1∶10 volume ratio of H3PO4, H2O2 and H2O is adopted to etch the hole array for 30 s. Images of scanning electron microscopy (SEM) and atomic force microscopy (AFM) show that the hole array has a period of 528 nm, etching depth of 124 nm, with perfect surface morphology, good fringe continuity and uniformity.