Abstract: TiAl-4522XD（Ti-45Al-2Mn-2Al-1B, at%） powders were densified under hot isostatic pressing at 1260 ℃, 150MPa, 4 h with the capsule of 20 steel, 45 steel and 304 stainless steel, respectively. The microstructure of the interface between the capsules and TiAl-4522XD alloy were investigated by optical microscope（OM）, scanning electron microscopy（SEM）. The element distribution at the interface was analyzed by Energy Dispersive Spectrometer（EDS） line scanning. Image-Pro Plus and Photoshop were used to quantitatively measure the width of the interfacial reaction layer. The results show that the brittle phases are formed at the interface between the TiAl-4522XD alloy and 20 steel capsule, which leads to the peeling between the alloy and the capsule, and there is obvious micro-crack at the side of the TiAl-4522XD alloy. The width of the interfacial reaction layer between 304 stainless steel and TiAl-4522XD alloy is largest, reaching 617 μm. The interface between 45 steel and TiAl-4522XD alloy is well bonded and the width of the reaction layer is only 1/3 of 304 stainless steel. Therefore, 45 steel is the most suitable capsule material for TiAl-4522XD alloy hot isostatic pressing.