MgO是II—VI族的一种多用途金属氧化物半导体材料，被广泛作为超导薄膜和半导体材料的生长衬底。本文采用基于密度泛函理论的第一性原理，进行了MgO材料体结构和表面结构、电荷密度、能带结构和电子态密度等性质的计算。计算结果表明：六角密排体结构MgO晶格常数分別为a=0.3258nm，c/a=1.618，与实验结果吻合较好。表面结构由8层原子和10 Å真空层的模型经弛豫得到；比较体结构和表面结构电荷密度，能带结构和电子态密度的计算结果，发现表面结构的MgO导带能量降低，带隙明显减小，各电子态之间的相互作用增强，呈现更强的金属性，利于作为衬底缓冲介质在其表面生长功能性半导体材料。

MgO is a group II-VI A multi-purpose metal-oxide and semiconductor materials. It has been widely used as a superconducting thin films and the growing substrate of the semiconductor materials. In this paper, applying the first principles based on density functional theory, calculations of the Structure and Property of MgO with the bulk and surface structure has been successful completed. The results show that: the hexagonal bulk MgO lattice constant a is 0.3258nm, c/a is 1.618, of which all are identical with the experimental results. After relaxation, the optimized Surface structure of MgO contains 8 layers and 10 Å vacuum in a period. Comparing the charge density, band structure and DOS of the bulk and surface structure, we find that the surface structure has a lower conduction band, which cause a smaller band gap and each electronic state has a stronger interaction, showing metallic properties, in favor of being a buffer in the growth of various functional semiconductor materials.