Abstract: A new airflow 8-armed olfactometer has been developed to test the kairomone responses of the predator.Coccinella scptempunctata.the.aphid.Aphis fabea, and its host plant.Vicia fabe.The results showed that the percentage of kairomone response of the adult predator to the host plant counted to 14.85%, as 1.7 times high as that to the aphid.that of larvae to the host plant was only 2.9%, as 1/6 times high as that to the aphid.The activity of the lalvae predator responding to the kairomone was much Iower than that of the adult.It is assumed that a decision in selection of host habitat location in the hature may be made by the adult predator and the larvae may be passive in searching the food choosen by their adults.