Effects of injection specific pressure and injection speed on the filling ability of semi-solid A356 alloy in rheo-casting were investigated.It is revealed that the filling pressure and the thickness of the billets have greatly affected the filling ability of semi-solid A356 Al alloy slurry prepared by the new method.The thicker the billets is

and the bigger the filling pressure is

the better the filling ability is

and vice verse.In order to obtain perfect castings

the filling pressure for the billets with 10 mm thickness should be equal to or more than 15 MPa and for the billets with 5 mm thickness equal to or more than 20 MPa.The injection velocity has great effects on the filling ability of the semi-solid A356 alloy slurry

and that the higher the injection is

the better the filling ability of the slurry is.For making sound castings

the filling velocity for the billets with 10 mm thickness should be equal to or more than 0.384 m/s while for the castings with 5 mm thickness equal to or more than 1.152 m/s.The billets with uniformly distributed microstructure in rheo-casting are beneficial to obtaining the A356 alloy die castings with perfect quality.