Abstract: OBJECTIVE To determine the lowest water activity(a_w) required for the growth of Burkholderia cepacia, and to observe the growth situation of Burkholderia cepacia in Baoji oral liquid and Qiangli loquat syrup, also to explore the relationship between a_w and the growth of Burkholderia cepacia, in order to provide a basis for the application of a_w to control microorganisms in the production of traditional Chinese medicine preparations. METHODS Adjusted the a_w of tryptic soy broth medium(TSB) with sodium chloride, and determined the a_w of TSB, Baoji oral liquid and Qiangli loquat syrup by determining instrument of a_w, respectively. Then incubated at 35 ℃ after inoculated Burkholderia cepacia, used the pour ptates for enumeration tests at the setting times, and draw the Burkholderia cepacia growth rate curve. RESULTS The lowest a_w of Burkholderia cepacia was 0.98, that of Baoji oral liquid and Qiangli loquat syrup was 0.99 and 0.93, respectively. Baoji oral liquid with high a_w could help the growth and reproduction of Burkholderia cepacia, while the growth and reproduction of Burkholderia cepacia in Qiangli loquat syrup with low a_w was inhibited. This result was consistent with USP <1112> “low a_w inhibits the growth of microorganisms in drugs”. CONCLUSION Reducing the a_w of traditional Chinese medicine in the production process can effectively reduce the risk of bacterial infection.