Based on the orthogonal experiment results, the significance of process parameters of near-β forging+solution and aging was analyzed. The effect of process parameters on the microstructure of TA15 alloy was discussed, and the proper process parameters were obtained to achieve the tri-modal microstructure with excellent properties. Results show that the deformation temperature, solution temperature, and solution duration are the most important process parameters, which affects mostly the volume fraction and diameter of the equiaxed α_p phase, the volume fraction of the lamellar α_s phase, and the thickness of the lamellar α_s phase, respectively. The optimal processing parameters are 970 °C/0.1 s^-1/deformation degree of 60%/water quenching+930 °C/1.5 h/air cooling+550 °C/5 h/air cooling.