Cellulose-based lightweight porous material has the advantages of light weight, high porosity, and low cost. So they are widely used in adsorption, catalysis, heat insulation and other fields. However, problems such as flammability and poor water resistance limit its scope of application. Compound modification can improve the above shortcomings and give it new characteristics. Therefore, it is necessary to fully understand the functional modification method and the wide application of lightweight porous composite materials. In this paper, by tracking the research and application progress of functional modification of cellulose-based lightweight porous materials at home and abroad, the basic properties and performance of cellulose-based lightweight porous materials are summarized, and the functions of cellulose-based composite lightweight porous materials are analyzed. Chemical modification methods and applications, the opportunities and challenges of cellulose-based composite lightweight porous materials in many fields are introduced in detail. The organic or inorganic materials are combined with cellulose to make lightweight porous materials. These materials can achieve flame retardant, absorption, electromagnetic shielding, electrical conductivity, hydrophobic, antibacterial and other functions, which can broaden the application range of cellulose-based lightweight porous materials in packaging, medical, battery and other fields.