In order to find a kind of economical,green,and effective microbial agent on the production of flue cured tobacco,Bacillus amyloliquefaciens FZB42 was selected to study its application effects at seedling and field period on growth and yield of flue cured tobacco by field trial.The results showed that microbial agent FZB42 promoted the growth of flue cured tobacco,reduced disease occurrence,increased the yield and improved the quality of tobacco leaves.Compared with the control,the yield and output value of tobacco leaves of the treatment with FZB42 applying at seedling stage were increased by 5.20% and 8.29%,respectively,and the treatment with FZB42 applying at field period were increased by 6.41% and 8.83%,while the treatment with FZB42 applying both at seedling and yield periods were increased by 9.18%和13.78% respectively,which was most effective.FZB42 was a kind of economical,green,and effective microbial agent which could promote the growth of flue cured tobacco,reduce disease occurrence,increase the yield and improve the quality of tobacco leaves.