Effects of benzoic acid on seed germination rate, root length, root diameter, root curvature and seedviability of cucumber and pumpkin was investigated. The results showed that with the increasing of the benzoic acidconcentration, seed germination rate, radicle length and seed viability declined, and Cucumis sativas decreased themost obvious, followed by cucurbita moschata, finally was cucurbita f1 cifolia. The bending angle of seeds and theroot diameter increased, Cucumis sativas increased the most, followed by cucurbita moschata, finally was cucurbitaf1 cifolia. So benzoic acid does more harmful to Cucumis sativas, then is cucurbita moschata, finally is cucurbita f1ci-folia.