In the article this is a new way to prepare Ti-6Al-4V alloy rod and blade by metal mold vacuum suction casting. The effects of hydrogen on the suction casting is also studied. It is found that the alloy melt can be sucked up easily by the mold and has a better fluidity because of H2. Hydrogen can make the electrical current for suction casting decrease sharply compared with the electrical current in Ar. Hydrogen can refine the grain size of the alloy rod and blade. Compared with the unhydrogenated specimen, the peak stress of the hydrogenated specimens increase about 20%, because hydrogen decreases the volume fraction and size of shrinkage porosity.