The polyphony board covered with aluminum foil of hollow wall is a new type of wall which heat insulation of aluminum foil has better heat preservation effect than cubage heat insulation. And inside temperature of air interlayer is in 10～30℃ when the thickness of air interlayer is in 20～100 mm. Calculation have indicated that average heat-insulating coefficient of air interlayer was in 0.6～0.7 (m²·℃)/W and equal to 490 mm brick wall (0.605 (m²·℃)/W) when difference temperature of air interlayer was in 2～10℃. Compared with the same thickness brick wall, material cost of the hollow wall with polyphony board covered with aluminum foil(610 mm) has increased by 5%. Its heat transfer-coefficient has decreased to 0.218 W/(m²·℃) from 1.098 W/(m²·℃). Compared with the same thickness air interlayer wall, the heat transfer-coefficient has decreased by 13%. Heat insulation of aluminum foil has more advantage than cubage heat insulation, such as light mass, good effect of moisture-proofing and vapor-isolating, low price, convenience of construction.