In order to explore the mechanism of anisotropy formation in Ti-6Al-4V alloy formed by selective laser melting (SLM), the compressive mechanical properties, microhardness, microstructure, and crystal orientation of SLM-formed Ti-6Al-4V alloys were systematically investigated. Based on this, the anisotropy of Ti-6Al-4V alloy formed by SLM was explored. The results show: Perform compression tests at room temperature at a strain rate of 10-3s-1, the compressive yield strength and microhardness are different with respect to the deposition direction, and the mechanical properties show some anisotropy. The microstructure of this alloy is columnar, and the morphology observed perpendicular to the deposition direction is columnar, while the morphology observed parallel to the deposition direction is equiaxed, all of which are hexagonal close-packed (HCP) internally α/α" Martensitic structure. Characterization of crystallographic orientation of samples using electron backscatter diffraction (EBSD) revealed that α" Preferential orientation along the approximate <0001> direction. Due to the high aspect ratio of columnar grains and the weak texture and poor symmetry of HCP, anisotropy occurs.