木塑复合材料（WPC）作为一种可再生建筑材料，因阻燃性能较差限制其安全使用。为提高材料的阻燃性能，文章将改性聚磷酸铵（M-APP）和膨胀石墨（EG）组成的复配阻燃剂加入WPC基体，制备WPC复合材料，并对其力学性能、阻燃性能和热稳定性进行测试。结果表明：相比未改性WPC，当M-APP和EG的比例为1∶1时，WPC/A₁/E₁的LOI值提高了44.4%，热释放速率峰值降低了80.1%，总烟量下降了91.6%。WPC/A₁/E₁的拉伸强度为25.1 MPa，与未改性WPC相比增加了3.7%。WPC/A₁/E₁的弯曲强度为45.1 MPa，与未改性WPC相比增加了1.1%。WPC/A₁/E₁残炭率为27.5%，与未改性WPC相比提升了76.3%。当M-APP和EG的比例为1∶1时，WPC/A₁/E₁具有较好的综合性能。

Wood-plastic composite (WPC) is a kind of renewable building material, but its poor flame retardancy limits its safe use. In order to improve the flame retardancy of WPC composites, the compound flame retardant composed of modified ammonium polyphosphate (M-APP) and expanded graphite (EG) was added into the WPC matrix to prepare WPC composites. The mechanical properties, flame retardancy and thermal stability of WPC composites were tested. Compared with unmodified WPC, when the ratio of M-APP to EG is 1:1, the LOI value of WPC/A₁/E₁ increases by 44.4%, the peak heat release rate decreases by 80.1%, and the total smoke production decreases by 91.6%. The tensile strength of WPC/A₁/E₁ is 25.1 MPa, which is 3.7% higher than that of unmodified WPC. The flexural strength of WPC/A₁/E₁ is 45.1 MPa, which is 1.1% higher than that of unmodified WPC. The carbon residue of WPC/A₁/E₁ is 27.5%, which increases by 76.3% compared with unmodified WPC. When the ratio of M-APP to EG is 1:1, WPC/A₁/E₁ has better comprehensive properties.