Si and Cu powders are added to Al powder and the mixtures compacted are heated at 620 or 600°C for 1 hr. in an argon atmosphere. Based on isothermal phase diagrams of Al-Si-Cu system(Al corner)at 620 and 600°C, the amounts of liquid phase are varied from10to60mass%. The relative densities of the sintered compacts are analyzed by using a regression analysis program; the relative densities are expressed as functions of sintering temperature, amount of liquid phase, ratio of Cu/(Cu+Si), and the others. Uniformity of shrinkage after liquid phase sintering is also analyzed.