Abstract: To disguss the influence on growth of flue-cured tobacco which comes from the usage of biological active agent, this research used three dosages of biological active agent in three test fields, and in contrast by a test field without biological active agent, then determined the agronomical characters, disease resistance, economic characters, appearance and innherent quality of primordial tobacco leaves. Results of ANOVA and T-test showed that the test fields which were used biological active agents, were better than contrast condition in agronomical characters, disease resistance, economic characters and innherent quality of primordial tobacco leaves in different degrees. And what’s more, the above indexs under the 2.25L/hm2 usage condition were significantly better than the 0.75L/hm2 and 1.5L/hm2 usage conditions. All the above results suggested that the usage of biological active agent has significant effect on the agronomical characters, disease resistance, economic benefits and innherent quality of primordial tobacco leaves.