In this paper, the nano-cutting and tensile model of monocrystalline γ-TiAl alloy was established by Large scale molecular dynamics simulations method. The objective is to analyze the effect of different cutting depths on tensile process of workpiece. For one thing, the relationship between lattice transformation and micro-defect evolution is studied in detail. For another, the influences of different cutting depths on stress-strain curve, the nucleation of dislocation and position of fracture surface are discussed. The research results show that amount of lattice transition rises with increases of cutting depth and consistents with micro-defect evolution during nano-cutting. Within a certain range of cutting depth, the yield stress and elastic modulus of workpiece are improved correspondingly. In addition, cutting depths have great influence on the position of dislocation nucleation and fracture surface of workpiece during tensile process. The dislocation of machined workpiece is nucleated at subsurface, while dislocation of unmachined workpiece is nucleated at edge of workpiece. The port position of workpiece is closer to drawing end with cutting depth increases.