Abstract: The effects of the nano BN and ZnO on the thermal decomposition, combustion and mechanical properties of wood flour-polyvinyl chloride (WF-PVC) composites were investigated. The flame retarded WF-PVC composites with nano-BN and ZnO were prepared by hot pressing. Thermogravimetric analysis (TG) test results show that the addition of BN and ZnO reduces the initial thermal degradation temperature of the composites, while significantly increases the pyrolysis residues of the composites. When the mass ratio of BN to ZnO is 1∶2, the residues content of the composites increases by 21.7%. The cone calorimeter combustion test results show that the addition of nano-BN and ZnO significantly improves the flame retardant properties of the composites. Compared with the pure WF-PVC, the addition of BN and ZnO effectively decreases the heat release and smoke release during combustion of the composites, the total heat release and total smoke emission are decreased by 18.2% and 48.9%, respectively. The mechanical properties of the composites were tested by the universal mechanical testing machine. The results show that the addition of the flame retardants has some negative effects on the mechanical properties of the composites. However, the flame retardants were compounded in a certain proportion, which could effectively reduce the damage to the mechanical properties of the composites. The flexural strength of the composites is reduced by 29.5% when the ZnO is added alone, while the flexural strength of the composites is decreased by 9.9% when the mass ratio of BN to ZnO is 2∶1.