Abstract: Hot pepper was susceptible to microorganism during harvest and processing.The dose (≤10kGy) was always used to control the growth of microorganism, but which could not meet the hygienic standard of irradiated spices.The present study mainly developed the irradiation dose and studied the effect of higher dose on color, pungency and volatiles of chilli powder.The result showed that irradiation did not affect the lightness (L* value) and redness (a* value) .However the yellow carotenoids might be more sensitive to irradiation because the yellowness (b* value) decreased 7.95% after an 18kGy irradiation.The capsanoids increased by 0.30%～9.06% after irradiation which enhanced the pungency.As the major component of essential oil of hot pepper, dipentene increased by 15.41% after 18kGy irradiation.However other volatiles of lower content had no obvious changes, so the irradiation had no significant effect on the flavor of chilli powder.