Stannous phosphate glass was prepared by melting stannous oxide and phosphorus pentoxide at a molar ratio of 50∶50 at 500 ℃，which was then combined with melamine by ionic bond to form melamine stannous phosphate glass ( MEPglass) ． Finally，MEPglass and aluminum diethylphosphinate ( AlPi) were employed to obtain halogen-free flame-retardancy of PA6． It is found that 0. 5% MEPglass and 9% AlPi can induce PA6 to reach UL94 V-0 @ 3. 2 mm rating，with a total relative addition reduction of 26. 9% ，as compared with the addition ( 13% ) of single AlPi，while the tensile strength improves by 8. 5% and the melt flow rate increases by 13. 3% ． Moreover，the results obtained from the cone calorimeter，thermogravimetry-infrared spectroscopy and thermogravimetric analysis of the samples，and scanning electron microscopy and X-ray energy spectrum analysis of carbon residue indicate that there is strong flame-retardant synergy of MEPglass and AlPi on PA6 in both the gas phase and the condensed phase．