By the soil treatment with tobacco in vegetable field, the larva number of striped flea beetle [ Plyllotreta striolata (F.)] decreased remarkably. The deterrent effect on the adults was 79 81%. The index of population trend (I-value) reduced to 1 882. The interfenence index of population control (IIPC) was 0 124 3, and its protective effect on seeding and yield of vegetable were 86 91% and 77 13% respectively. The control mechanism of tobacco on the population of striped flea beetle was its deterrent effect significantly.