Abstract: In order to systematically investigate the microstructure transformation mechanism of selective laser melting(SLM) formed TA17 alloy, the microstructures of TA17 alloy were characterized and analyzed under SLM and SLM + heat treatment(HT). The results show that under extremely fast cooling conditions, the microstructure of TA17 is dominated by fine needle-shape α phase, with plate textures 0 0 0 1 < 1 0 −1 0 >, 1 0 −1 0 < 1 1 −2 0 > and 1 1 −2 0 < 1 0 −1 0 > as main types; and two types of variants, namely the 60°/1 1 −2 0 and 60.83°/−1.377 −1 2.377 0.359, are inclined to be generated. While after a treatment of 950 °C/2 h + air cooling, a dual state α structure is formed on the TA17 alloy with typical equiaxed grains and a plate-like morphology. With the increase in the degree of texture dispersion, the strength decreased significantly. There was also a change in variant selection, as the proportion of 60°/1 1 −2 0 and 60.83°/−1.377 −1 2.377 0.359 variants decreased significantly, 63.26°/−10 5 5 −3 become the major variant.