Polypropylene (PP) has excellent mechanical and chemical properties. Thus, it is used in a wide range of applications. However, high flammability of PP limits its application in remarkable flame-retardant standards fields [1]. Some of halogenated flame retardants (FRs) are restricted by the European Community directives ROHs, WEEE and REACH. Now metallic hydroxides are widely used in industry, but the high loading (~ 60 wt.%) seriously destroys the mechanical properties of flame retardant PP. Intumescent flame retardant (IFR) is established in polymeric materials since it is regarded as a safe and environmentally friendly flame retardant [2-3]. However, some components of traditional IFR are made from low molecular mass components which might undergo migration and thermal degradation during processing. In this work, a multifunctional flame retardant (MFR) was prepared based on ammonium polyphosphate (APP). In addition, we used electron beam (EB) technology for inducing of chemical couplings between MFR and PP. The results showed that MFR was excellent flame retardant crosslinker for PP. Further, MFR exhibited outstanding flame retardancy. In comparison to the traditional APP, the LOI value of PP/MFR composites (with 20~35 wt. % MFR) were more than 30 and effective melt drop resistance in UL-94 test; in cone calorimeter test, reduction of the peak heat release rate (~ 41 %), total heat release (~ 53 %) and smoke production (85 %). Finally, the thermal stability and tensile properties of these designed flame retarded PP composites were improved by EB treatment. Based on these results high performance fire retardant polymer nanocomposites might be developed for industrial applications such as insulated material of wire, cable, etc.