Abstract: A use of citronellol in preparing a preparation for promoting an expression of a virulence gene toxA of Pseudomonas aeruginosa is disclosed. It was found that citronellol slightly inhibits the growth of a Pseudomonas aeruginosa PAO1 strain and can promote the transcription of the toxA of Pseudomonas aeruginosa, which can increase the yield of an exotoxin A, namely, an encoded product of toxA. Therefore, citronellol is applicable to the preparation of a preparation for promoting the expression of the virulence gene toxA of Pseudomonas aeruginosa.