Abstract: In order to study the activity of cinnamate in crops, 2,4-dichloro-cinnamic acid ethyl ester was synthesis starting from 2,4-dichloro-cinnamic acid, and 2,4-dichloro-cinnamate was determined by 1H NMR. The dosage form of the product was researched. The results showed that, it had high promoted rate 21% on peanuts, 16.7% on ginger, 22.4% on corn with 500 times, it displayed that these compounds have high biological activity and production increasing performance.