The traditional extrusion and thixo-extrusion processes of wrought magnesium alloy were studied with both computer numerical simulation and experimental methods. The thixo-extrusion set-up was made. The constitutive model of semi-solid AZ61 alloy was established in our prior literature. The comparison of two forming processes had been done. Results indicated that smaller load and uniform strain & stress were acquired in thixo-extrusion process. Simulation results were in good agreement with experimental ones.