The tensile and compressive mechanical properties of gold nanotubes in different crystal orientations as well as the tensile mechanical properties of the same thinkness of gold nanotubes at different radius. are investigated using the molecular dynamics simulation method. In the simulation, we select embedded atom method as the interatomic potential function. The result shows that mechanical properties in the tensile and compressive process in different crystallographic orientations are dramatically different from each other, where the yield strength of the direction is the highest and the yield strength and the Young's modulus in the direction are less than in the and crystal orientation. The yield strength has no major changes when the radius is less than 3.0 nm, but it obviously decreases with the increase of the radius when the radius is larger than 3.0 nm.