Booster vacuum casting is an advanced technique developed on the basis of traditional casting,its principles can be summed up as vacuum-pouring and solidification pressure, The paper is the use of vacuum booster technology ,producing weight of about 60 kg, size of 1200×600mm and 2-20 mm wall thickness of the aluminum alloy large complex castings-electronic ark（ZL101）.By the casting analysis and production practice, designing reasonable technics parameter: Smelting between 720℃ and 730℃, the degree of vacuum-pouring is -0.0975MPa, and the solidification pressure of 0.4-0.7MP, There is no shrinkage, no pinholes on the large complex aluminum alloy casting surface,by using X-ray. Casting structure is thickening and the eutectic structure tiny ,under the microscope. Its tensile strength would attain 245MP and elongation percentage 4.5%.