The main purpose of this investigation is to develop a mathematical relationship for the flow strength based on microstructure evolution during the hot forming of titanium aluminide. For engineering applications, gamma titanium-aluminide which is composed of 46-50 at.% Al is desired in a duplex grain microstructure. Thermomechanical processing of this alloy requires a temperature of 0.60-0.75 T-M (melting point) in order to properly control the microstructure and grain growth. Compression tests were conducted in the temperature range between 950-1100 degreesC at strain rates of 0.001/s and 0.1/s to develop a duplex phase microstructure, gamma with 5-20% alpha (2). By using the experimental data, mathematical relationships were verified for different stages of hardening, recovery, recrystallization, and grain growth. The simulation was based on the theory used in the Sandstrom and Lagneborg model and the numerical analysis approach developed by Pietrzyk. The simulation proved that the model and numerical simulation well-presented the compression deformation of titanium-aluminide alloys at constant strain rates.