Timber structure buildings are very popular in the Europe and America that almost occupied 90% of residential house (Single house or Villa). According to the global market statistics in 2011, the buildings made by North American wood and its matching materials took 70% of global wood structure buildings market share. Before 1980s, rock wool and glass wool was chosen to insulate American wood structure buildings, but then they were found having many Carcinogen bad to human’s health and with inefficient insulation performance. In the 1990s, the American Wood Structure Association proposed that all the wood structure buildings shall apply low density polyurethane foam for heat insulation. It has excellent heat and sound insulation performance, safe and Eco friendly. SWD low density polyurethane spray foam developed by SWD Urethane., USA applied with full-water foaming method, it will not destroy the ozonosphere, environmentally friendly, energy efficient, good insulation effect and price competitive. It has become a priority product for wood structure villa insulation in the American market.