基于密度泛函理论体系下的广义梯度近似(GGA)方法,利用第一性原理计算了不同压强下六方纤锌矿AlN的晶体结构、电子结构和光学性质.通过比较压力作用下能带结构的变化行为,得出AlN在16.7 GPa附近存在等结构相变,即由直接带隙结构转变为间接带隙结构.结合电子结构分析了高压对AlN光学性质的影响,发现在压力的作用下AlN吸收光谱有蓝移的趋势. Based on the generalized gradient approximation (GGA) method under the density functional theory system, the crystal structure, electronic structure and optical properties of hexagonal wurtzite AlN under different pressures were calculated by first principles. The results show that the AlN has an isostructural transformation near the band gap of 16.7 GPa, that is, the direct band gap structure changes to an indirect band gap structure.The influence of high pressure on the optical properties of AlN is analyzed by electron structure and it is found that AlN absorption under the pressure The spectrum has a blue-shift trend.