Abstract: The chitin nanofibers(CNF)/montmorillonite(MMT) intercalated composites were prepared by using the method of ultrasonic miscibility-vacuum filtration.The structure of CNF/MMT was characterized by FE-SEM and FTIR, and the effects of MMT content on the mechanical properties, water absorption performance, coefficient of thermal expansion(CTE) and thermal stability of the composites were investigated.The results show that, when the content of MMT is low, the bonding state of CNF and MMT is relatively good, CNF are more evenly dispersed in lamellar MMT interlayer, which forms CNF/MMT composites.The mechanical properties and water absorption of the composites decrease with the increasing of MMT content.CTE of the composites reduces with the the increasing of CNF because CNF could suppress the thermal expansion of MMT.The thermal stability of CNF/MMT composites can be effectively improved through adding MMT since it can reduce the mass loss rate of composites and improve the initial degradation temperature.