TiAl alloys are considered potential structural materials because of their low density, good high-temperature strength, and creep resistance. However, their low-temperature brittleness and poor high-temperature workability lead to narrow processing windows, which hinder their industrial applications, low pressure turbine blades of high-performance engines and thermal protection system for hypersonic space vehicles, for instance. Extensive studies on alloying and hot mechanical processes have been conducted to control the microstructure and then enhance the inherent ductility of TiAl alloys. Alloying is considered as an effective method to stabilize softening phases or refine grains to optimize microstructural homogeneity and hot workability. Thus, β-solidifying γ-TiAl alloys represented by Ti-(40-45)Al-(2-8)Nb-(1-8)(Cr, Mn, V, Mo)-(0-0.5)(B, C) (atomic fraction, %) alloys were designed. Nb and Mo are added as β-phase stabilizers. Meanwhile, B, C, and Y serve as grain refiners, and they are added to increase the hot workability. However, multiple phases, precipitation, and corresponding phase transformations are introduced, leading to complex flow localization and deformation incompatibility. Therefore, considerable effort has been exerted on thermo-mechanical processing to improve the microstructural homogeneity of these alloys. The interaction among work hardening, recovery, recrystallization, and multiphase transformation under different deformation conditions easily aggravates flow localization and deformation incompatibility, which are inadequately studied. Therefore, a comprehensive understanding of the deformation behavior among multiphase β-solidifying γ-TiAl alloys is necessary. In this work, the uniaxial hot compressions of the β-solidifying γ-TiAl alloys with the nominal compositions of Ti-44Al-5Nb-1Mo and Ti-44Al-5Nb-1Mo-2V-0.2B were conducted. The microstructure of the alloys under different temperatures and strain rates was contrastively studied using SEM-BSE and TEM. The effects of V and B on the microstructural evolutions and deformation mechanisms were analyzed. The results indicated that the addition of V and B contributed considerable differences in microstructure and thermal mechanical sensibility. The Ti-44Al-5Nb-1Mo-2V-0.2B alloy showed high-temperature deformation ability. The deflection of residual lamellae and the formation of shear bands were the main deformation mechanisms, and a nearly lamellar microstructure with a nonuniform grain size was easily generated at 1250^oC for the Ti-44Al-5Nb-1Mo alloy. On the contrary, for the Ti-44Al-5Nb-1Mo-2V-0.2B alloy, the deformation-induced lamellae decomposition of lamellar (α/γ) (L(α/γ) for short)→α + γ + β/B2 and γ→α and the spheroidization or dynamic recrystallization of α and B2 grains could be promoted with the increase of deformation temperatures and decrease of strain rates. Consequently, the microstructural homogeneity was greatly improved. Furthermore, specific deformation conditions of the microstructural control, including a nearly full lamellar and nearly duplex microstructure, were presented in this work.