Abstract: Effect of plastic mulch on sucker development in flue-cured tobacco was studied by three cultivation treatments:sticking seedling out of plastic film on the 20th day after setting, sticking seedling out of plastic film while setting and setting seedling in uncovered soils. The result showed that plastic mulch could promote sucker development as well as tobacco plant grow th. The effect of the first treatment was most significant. The cause of promoting effect of plastic mulch on sucker development was discussed.