The process control of patterned sapphire substrates fabricated by inductively coupled plasma（ICP） etcher is researched in this paper. In fabrication, the 100 mm flat sapphire wafers with C axis (0001) orientation are selected as experimental samples, and the patterned sapphire substrates with conical patter shape are fabricated by photolithographic etching technique and ICP etching technique. Finally，the fabricated substrates are measured and analyzed by the scanning electron microscope. The measured and analyzed results show that the diameter of single conical pattern on the substrate surface is (3.45±0.25) μm, the etching height/depth is (1.75±0.25) μm, and the uniformity of the whole substrate is controlled within 3%.