ABSTRACT In order to improve the thermal insulation and smoking properties of expanded vermiculite matrix composites, a kind of expanded vermiculite (EV)/chitosan (CS) composites was prepared by hot pressing. The effects of CS on smoke density, fire-resistance, insulation, and mechanical properties of the EV/CS composites were studied. The results show that with the increase of CS content, the smoke absorption performance and energy storage modulus of the composites is improved. Thermogravimetric (TG) analysis shows that the thermal stability of the EV/CS composite is improved by the presence of chitosan. The pores appear on the surface of the composites after the single-side fire-resistance test. After that, the thermal conductivity of the composites gradually decreases and the insulation performance is improved as the CS content increases. The CS carbonized during the preparation of the composites and thermal decomposition during the test. The morphology results show phase separation of the composites, and the porosity of the composites increases after the test. The reticular structure formed between the EV particles, sodium silicate, and CS molecules reduces the strength loss of the composites.