In order to better understand the dependence of bioactivities on the struct
ures of the fluorine - containing new pesticidal compounds and to build up
significant structure - bioactivity models, the relationships between the s
tructures and two different kinds of bioactivities of 33 fluorine - contain
ing compounds have been investigated by classical QSAR methods. The obtaine
d bioactive model for cucumber disease has a good capability for the explan
ation and prediction. Based on this model some new active structures were d
esigned. However, no significant model was obtained for the bioactive data
of water-melon disease. This work resulted in a typical QSAR studying schem
e in which the cluster analysis is applied, followed by the multivariate st
atistical methods for a deeper investigation.