Aiming at the minimum cutting thickness existing in mesoscopic cutting process, the formation mechanism of the minimum cutting thickness was described, and the theoretical model of minimum cutting thickness based on tool edge radius and friction coefficient between workpiece and tool was proposed, and the cutting parameters were substituted into the theoretical model, and the minimum cutting thickness is calculated to be 2.3 μm. Taking Ti6 Al4 V titanium alloy as the research object, the 2 D cutting model of titanium alloy was established by using ABAQUS finite element software, and the simulation results show that the minimum cutting thickness is between 2 μm～3 μm, which verifies the correctness of the theoretical model of minimum cutting thickness. The influence of cutting edge radius and friction coefficient between workpiece and tool on minimum cutting thickness is analyzed, and the results show that the minimum cutting thickness is directly proportional to the tool edge radius and inversely proportional to the friction coefficient between the workpiece and the tool.