A prealloyed powder hot isostatic pressing (HIP) technique was utilized to fabricate a TiAl-4522XD alloy. The effects of HIP processing parameters (temperature and powder particle size) on the microstructure and mechanical properties of TiAl-4522XD alloys were investigated. Densification cannot be achieved at a HIP temperature of 1 200 ℃, with prior particle boundaries (PPBS) in the microstructure, resulting in a low matrix strength. At a HIP temperature of 1 260 ℃, complete densification is achieved, the PPBS disappears, and the tensile strength of the alloy significantly increases. When the hot pressing temperature is increased to 1 300 ℃, γ grains and borides rapidly grow, microcracks appear at the γ/α2 phase boundaries under thermal stress, and the tensile strengths at both room temperature and high temperatures decrease compared with those at 1 260 ℃. HIP samples with different particle sizes were fabricated at 1 260 ℃ for 4 h. The results show that all the samples reached the theoretical density of the TiAl-4522XD alloy. For the particle size ranges of 150~212 and 45~212 μm, the deformation amount of powder particles is uneven, with microcracks present in the hot-pressed samples; for the particle size range of 45~150 μm, the hot-pressed samples have uniform and fine microstructures without obvious defects. Additionally, the vacuum degree during powder loading and degassing must reach 10-3 Pa; otherwise, it affects the density of the microstructure and the uniformity of powder deformation, leading to  cracks at the PPBS. On the basis of these results, the optimal HIP process is achieved: the powder particle size range is 45~150 μm, and the HIP parameters are 1 260 ℃/4 h/10-3 Pa. Under these conditions, a uniform and dense near-γ microstructure is obtained, with a room temperature tensile strength of (698.0±2.0) MPa and a high-temperature tensile strength of (504.5±2.5) MPa.