Abstract: We made entirely determination and analysis for "nuisance-free of Kaifeng city, proving that taking with lay down ciltivating plan the amount of heavy metal and -organic chlorine pesticide in watermelon are less than the permissive amount of national index for food. The riping period and growing period of "nuisance-free watermelon" have no obvious difference from similar watermelon. The transfer law of their poisonous remaining quantity is root>stemand leaf > skin and palp. The results showed that the organic chlorine were enriched in watermelon, but the heavy metals were not enriched in watermelon.The remaning quantity of β type in all isomers of benzenehexachlolride is the most in watermelon and P type remaining quantity of riping watermelon is more thanthat of growing watermelon.