Contents of MDA in mango peel went up continuously under fluoride pollution, and it's SOD, CAT, POX enzyme activities increased in initiative developmental stage and reached a climax in 33 days after flower shedding and descended rapidly later. As a result, black tip symptoms were appeared. Fruit bagging was a physical measure to isolate fluoride pollution and early bagging pulled the enzyme activities back to normal level so mango fruit could developed normally; However, fruit bagged in late period, enzyme activities were disordered and black tip symptoms appeared. Harmful ethylene in mango fruit was excreted in 33 days after flower shedding and fruit black tip symptoms appeared heavy when fruit exposed under fluoride pollution. Black tip symptoms can be reduced effectively by decreasing the contents of harmful ethylene via fruit bagging before 33 days after flower shedding.