By using self-designed continuous rheo-extrusion process, AZ61 alloy wire with the diameter of Φ10 mm was fabricated. Under the actions of kneading and shearing by the roll, microstructures of the alloy gradually evolve from dendrites at the pouring entrance to the fine equiaxed and spherical grains at the extrusion zone. During the extrusion forming process, solid structures in the central part have a small deformation, but that in the outside have a large deformation, and ultra-fine grain microstructures come into being in the arc flow part. Under proper process conditions, the microstructures on the transaction of the product are good and show the character of two-phase plastic flow. Casting temperature can affect solid fraction and further induces a great influence on the forming process; proper casting temperature is about 650 ℃.