lightweight composite paper honeycomb core wallboard as green building materials and low carbon product of modern life, its lightweight and energy saving, environmental protection, easy construction which other wallboards can't reach, but in actual use, the residents reflects its sound insulation performance is not very well, The lightweight composite paper honeycomb core wallboardand is composite with two rigid panel and paper honeycomb core which is in the middle of the wallboard. However, at present, people rarely Study on Sound Insulation Property of lightweight composite paper honeycomb core wallboard, so take the lightweight composite paper honeycomb core wallboard as the research object, through several sets of Different Specifications wallboard of experiment test,, the results showed that:The sound isolation property of calcium silicate panel is better than Gesso panel’s. The thick panel’s sound isolation property is better than the thin one. At the same thickness, the more layers of paper honeycomb core, the better sound isolation effect. Increase the layer number of paper honeycomb core has remarkable effect on sound isolation property.