The semi-solid AZ61 wrought magnesium alloy was fabricated by mechanical stirring method. Thixo-forging set-up were designed and made. The traditional forging and thixo-forging processes of AZ61 magnesium alloy were studied with both computer numerical simulation and experimental methods. The constitutive model of semi-solid AZ61 alloy was established in our prior literature. The differences between traditional forging and thixo-forging processes were analyzed. Results indicated that smaller load and uniform strain & stress were acquired in thixo-extrusion process. Simulation results were good agreement with experimental ones.