In order to investigate the effects of lamellar thickness and γ/α2 interface on the deformation and mechanical properties of dual-phase TiAl alloy during nano-indentation process, molecular dynamics method was used to simulate the nano-indentation process of γ and α2 phases with diamond indentation perpendicular to γ/α2 interface for five kinds of dual-phase TiAl alloy models. The results show that the hardness of the material increase with the decrease of the lamellar thickness. When the lamellar thickness decreases to 7nm, the hardness of the material reach the maximum value. However, when the lamellar thickness further decreases, the hardness of the material decrease. The elastic modulus of the material changes with the thickness of lamellar and is proportional to the hardness. In addition, the deformation behavior of γ phase in the nano-indentation process is mainly the stacking fault of {111} plane, and the γ/α2 interface can effectively hinder the dislocation movement. The deformation behavior of α2 phase is mainly the stacking fault of (0001) base plane. The Schockley partial dislocation motion formed on the base plane lead to the phase transformation on the material surface. The prismatic plane slip system is activated.