By means of life table and Interference index of population control(IIPC), the effects of secondary substance of non preferable plant on Conopomorpha sinensis Bradley were studied in Shenzhen, Guangdong Province. The results showed that the alcohol extracts of Tephrosia vogelli, Eupatorium odoratum and Eucalyptus robusta which were selected from 24 species of plants had better repelling effect on adults ovipositting of Conopomorpha sinensis . When the alcohol extracts of Eupatorium odoratum, Tephrosia vogelli and Eucalyptus robusta spayed in the litchi orchard, the trend index of population of Conopomorpha sinensis in treatment were 2 817,3 206 and 3 863, respectively. The interference index of population control of Conopomorpha sinensis in treatment of the alcohol extracts of Eupatorium odoratum, Tephrosia vogelli and Eucalyptus robusta were 0 209, 0 238 and 0 286, respectively, while the fruit protective effects were 79 1%, 76 2% and 71 4%, respectively.