Escherichia coli TRTH was taken as the starting strain for tryptophan production． The succinic acid was added with glucose after 10 h fermentation in the 30 L fermenter to reduce the accumulation of metabolic inhibitors and increase the L-tryptophan yield． When 1 g /L succinic acid was added，the biomass，L-tryptophan production and glucose conversion rate were increased by 5． 4%，9． 98% and 4% respectively，while the accumulation of acetic acid was decreased by 9． 5%． The results suggests that the addition of 1 g /L succinic acid can increase the production of L-tryptophan，reduce the accumulation of the acetic acid and improve the glucose conversion rate．