Five different copper structures,including atomic chains atomic monolayers and bulk crystal,have been calculated by full-potential augmented plane wave method.For atomic mono-layers,the hexagon structure was found to be energetic favourable compared with the square structure,and the nearest bond length was also longer.For atomic chains,the same result has been obtained when the equilateral zigzag structure was compared with the linear structure.The calculated density of states (DOS) of the zigzag structure showed some unusual properties,and a band gap has been found.The DOS has been analyzed for different structures to find the relations between the electronic properties and the atomic structures.