The effect of poly(dianilinephosphazene) (PDAP) on the processability, thermal behavior, crystallinity, morphology, mechanical properties, and flammability behavior of low-density polyethylene (LDPE) was studied. Plasticorder traces of PDAP/LDPE blends implied good processability and miscibility. Thermogravimetric analysis showed that PDAP improved the thermal stability of LDPE. X-ray diffraction results indicated that PDAP was a semicrystalline polymer, and the crystallinity of the blends decreased with increasing PDAP content. A new reflection at 20 = 23.15degrees was found in wide-angle X-ray diffraction spectra of the blends, indicating that these two components interacted with one another. The scanning electron microscopy microstructures of the blends also supported these findings. Moreover, PDAP substantially enhanced the limited oxygen index and elongation at break of LDPE.