Two-dimensional AlN photonic crystals (PCs) with varying periodicity/diameter down to 15075 nm were fabricated. Deep ultraviolet photoluminescence spectroscopy has been employed to study the optical properties of AlN PCs. With PC formation, a 20-fold enhancement in the band edge emission intensity at 208 nm over unpatterned AlN epilayer has been observed. The emission intensity increases with decreasing lattice constant of AlN PCs. However, the spectral peak energy decreases with decreasing lattice constant, indicating a possible release of compressive stresses as a result of PC formation. Successful fabrication of AlN PCs opens up new opportunities for exploring novel physical phenomena in the artificially structured photonic band gap material system and their applications, particularly in the area of deep UV photonics.