Abstract: In this paper,sendies were made of the effect of both aqueous extracts and ethanol extracts of olive leaves on the seed germination of tomato, grass, corn, wheat and lawn, and the determination was conducted on the length and weight of stems and roots,the germination potential and germination rate. The results showed that extracts had different influences on various seeds. These influences were related with solvent types,extract concentration and seed species. The roots were inhibited much more than the stems. The low concentration extract would promote the seed germination however the inhibition would occurr with the high concentration extract. Both soluble alkaloid and alcohol-alkaloid were found in olive leaves, and they exhibited different effects on various seeds.