Abstract: A novel P-N-Si synergistic flame retardant（Al（MPP）-KH550）was prepared by reaction of aluminum methyl propionylphosphinate（Al（MPP））and γ-aminopropyltriethoxysilane（KH550）. The structure and thermal degradation behavior of the product were characterized with FTIR，XRF and TGA. As flame retardant being used in PA66，the limiting oxygen index（LOI）of PA66 with 20 wt% filler loading improved from 19. 3% to 29. 6%，and the vertical burning test reached UL94 V-0 grade. Moreover，not only the heat release rate（HRR）of PA66 was effectively inhibited with the adding of Al（MPP）-KH550，but also the formation of a dense carbon layer was promoted.

Key words: P-N-Si synergistic effect, flame retardant, synthesis, PA66