The disadvantages of TiAl alloys such as narrow hot-working window ( forging, hot extrusion, rolling, etc. ), poor high temperature deformability and brittleness at room temperature limit its applications in actual projects. The research state of effects of alloying additions on hot deformation processing and superplasticity of TiAl based alloys was reviewed. The effects of alloying additions on hot deformation processing of TiAl alloys were discussed from the aspects of the crystal structure of TiAl alloys, the fraction of β phase, microstructures, activation energy respectively. The principles and the developing trend that alloying method improves hot deformability of TiAl based alloys was finally proposed.