An inventive method of flexible thixo-extrusion technology was put forward, in which the stress status on flow front surface was controlled during thixo-forming. A complex part with different dimensions in three axis directions was designed. The velocity of sliding die was controlled by spring. This kind of die construction could make sure that the flow front of the slurry was always in compressive stress status. The velocity field, effective strain fields, effective stress fields were simulated and analyzed. The results showed that the thixo-extruded complex part was produced under compressive forming state, which forecast good mechanical properties in the practical experiment.