Ti-5Al-5Mo-5V-1Fe-1Cr Ti alloy is an important aviation material. The microstructure heterogeneity of the alloy during isothermal compression is revealed in this work. The alloy is fabricated via the consumable vacuum arc-remelting furnace. The as-cast ingot is subjected to thermo-mechanical processing and heat treatment. Isothermal compression tests are conducted subsequently. The cylindrical specimens are machined from the heat-treated rods. The two ends of the specimens are not rubbed and polished. The local large deformation zones are observed in the specimens undergoing isothermal compression, which can cause crack nucleation in the material when the material bears load. The microstructural phenomenon is investigated in this work.