Abstract: 【Objective】Foam biomass polyurethane rigid foam(LP-PU)by liquefaction products of salix(LP).【Method】Mix the organic montmorillonite(OMMT)and liquefaction products of salix(LP)under the condition of ultrasonic wave concussion and subsequently put the mixture(LP-OMMT)and isocyanate together to foam. The structure and property of obtained foam were characterized and tested by means of FTIR, XRD, TEM and TG. 【Result】The experimental results indicated that, under ultrasonic wave concussion, the FTIR shows that the addition of OMMT had increased the hydrogen bond index and cohesive energy of foam. It was observed from XRD and TEM images that the layer spacing of OMMT was 5.5 nm and it was more easily to disperse in the form of intercalation and the form of exfoliation. The TG curve of the materials moved to higher temperature and the carbon yield of foam was 38.51%. Therefore, the thermostability value increased. Moreover, the density of foam was 34.9% less than pure foam, while the compression strength almost remained unchanged. The flame retardant property reinforced, as the oxygen index of foam increased to 37.2%.【Conclusion】Intercalated or exfoliated OMMT can be prepared by adding just the right amount, which significantly improved themechanical properties, thermal stability and flame retardance of materials.