Abstract: 【Objective】 Quadrastichus erythrinae Kim is a new invasive pest on host plant Erythrina spp. in China. Investigation on interaction between the pest and its host plant can be helpful for developing control strategies. 【Method】 The olfactory behavioral responses of the adult wasps toward eleven host plant volatiles were tested under the Y-type olfactometer. 【Result and conclusion】 Adults of Q. erythrinae showed strong responses to all tested volatiles. Wasps displayed different behavioral responses to different substances in different concentrations. Different olfactory parameters, such as olfactory reactive rate, olfactory selective reactive rate, and olfactory selective coefficient were used to value the wasps’ responses. The selective reaction rates of volatiles were above 50% except for compounds of benzonitile, which became more intense with the increase of compound concentration. The adult wasps were negatively chemotactic when under the concentration of unvarnished benzonitrile and 10-fold diluted benzonitrile, which showed significant differences compared with other volatiles.