The dynamical shear deformation induced hexagonal close-packed （HCP）face-centred cubic （FCC） processes in TiAl/Ti3Al system are investigated by the molecular dynamics method. The details of the dislocation initiation， the microstructure evolution and the force field effect are presented and discussed. The analyses of the potential variation and the structural snapshots show that the shear deformation is related to the “stick-slip” behaviour. The interface can transit the energy and counterpoise the deformation between the hetero-phases. The HCP-Ti3Al （FCC-TiAl） shows obvious （little） covariant deformation stage before the initiation of the fault transition. For HCP-Ti3Al， the final structure is the continued FCC stacking in a region with the large force field， and the FCC and HCP plates alternatively occur near the interface. For FCC-TiAl， twin and SISF are the main remnants， and the meta-stable HCP phase may occur with the increment of the force field.