TA15 samples with different turning numbers were prepared by high-pressure torsion process. Using metallographic observation, X - ray diffraction analysis and microhardness test, the effects of high-pressure torsion on the microstructure and properties of TA15 titanium alloy were analyzed. The experimental results show that the microstructures of the specimens are not evenly distributed in the radial direction after deformation. With the increase of turning numbers, the coarse primary equiaxed α phase gradually decreases and the grain refinement effect is obvious. And the material appears preferential orientation in the (200) crystal. After the high-pressure torsional deformation, the size of the sub-crystal decreases, while the microstrain and dislocation density increase significantly. In addition, the microhardness of the deformed specimens increases remarkably. Moreover, the hardness increases with the number of torsion turns increasing. When the number of twists turns is greater than 4, the microhardness tends to a saturation value.