Abstract: Flame retardance and smoke suppression mechanisms of triphenyl phosphate (TPP) and zinc stannate(ZS) alone and together in the anhydride cured epoxy resin(EP) were studied by limited oxygen index(LOI), thermogravimetry analysis(TGA) and NBS techniques. The results indicate that TPP alone is an effective fire retardant in EP, can stabilize EP at high temperature, and lowers the mass loss rate of EP. The mechanism of action of TPP in EP is the condensed-phase and gas phase. TPP alone is an effective smoke suppressant. Liquid phosphorus-containing compounds formed in the decomposition of TPP can adsorb the small amount of smoke particles. ZS is ineffective fire retardant in EP. At 30 phr, ZS can decrease the maximum smoke density of EP from 796.4 to 491.7. ZS can catalyze the thermal degradation of EP and prevent multicycloaromatic compounds being formed. But ZS can decrease the value of t (16). So ZS as a smoke suppress agent is not suitable to EP. The combination of TPP and ZS show the flame retardant synergism effect.