Insulation materials can effectively reduce heat loss by conduction, thereby conserving energy in buildings. Traditional insulation materials usually consist of organic compounds, which are flammable. Despite the application of inorganic materials, such as fiberglass (GF), for their flame-retardant properties, their poor insulating performance and difficulties in dispersion and molding limit their use in construction. Therefore, creating a composite that effectively combines the high thermal insulation properties of organic materials with the high flame resistance of inorganic materials holds significant importance, yet poses substantial challenges. Herein, an Anisotropic Noncombustible Nanocomposite based on Fiberglass-Chitosan (ANNFC) has been prepared. GF was uniformly dispersed into the chitosan (CS) solution though hydrogen bonding. The ANNFC with anisotropic layered structures was prepared through a freeze-orientation process. The as-prepared ANNFC reached a high limiting oxygen index (LOI) of 99.48%, exhibited a low heat release rate (peak at 26 kW m −2 ), a low smoke production rate (peak at 0.00143 m 2 s −1 ), and a high compressive modulus (3.65 MPa). As a conceptual demonstration, a mini house was constructed using ANNFC. After being baked at a high temperature of 50 °C for 1 h, the interior of the ANNFC house maintained a relatively steady temperature of 37 °C. Therefore, the successfully constructed ANNFC provided a feasible path for fabricating thermal insulation materials for construction.