Marigold was taken as material and photoactivated pesticide α-terthienyl was extracted with chloroform to study the fresh-keeping effect of marigold extract to cherry tomato. Index change of cherry tomato in storage with marigold extract was studied. The experiment result showed that the α-terthienyl containing extract can reduce the water loss rate and rot rate of cherry tomato in storage, which can also delay the decreasing of Vc in cherry tomato; the fresh-keeping effect of α-terthienyl extract is better than classical single chitsan composition preservative.