To evaluate the sterilization effect of electron beam irradiation on Tibetan medicine Bawei Chenxiang powder and the influence on the active ingredients, medicine samples were irradiated with electron beam at doses of 0 kGy, 5 kGy, 7 kGy, 10 kGy, and ⁶⁰Co γ at 7 kGy. The microbial and active substance costunolide levels were measured within 7 d after irradiation and after accelerated storage at 49 ℃ for 3 months, respectively. The results showed that electron beam and ⁶⁰Co γ irradiation significantly reduced the total number of microorganisms in Bawei Chenxiang powder. Irradiation by electron beams at 5 kGy and 10 kGy reduced the total number of microorganisms in Bawei Chenxiang powder to the maximum requirement suggested by the Chinese Pharmacopoeia without significantly decreasing the amount of active ingredient. In conclusion, electron beam irradiation can effectively improve the microbial index of Bawei Chenxing powder, and 5 kGy is the optimal processing dose for this purpose.