Abstract: Objective To investigate the optimal high cell density fermentation conditions of recombinant E.coli BL21/pET- 24a/hVEGF,sub>121 expressing recombinant human vascular endothelial growth factor (rhVEGF₁₂₁).Methods The effects of the composition of the fermentation medium, induction time and fed-batch carbon sources on the expression level of rhVEGF₁₂₁ and cell output were analyzed.Results and Conclusion When cultured in modified M9 medium and induced for 4h in the presence of 0.5mmol/L IPTG at 37℃ with glycerol as the carbon sources by continuous fed-batch mode, the recombinant E.coli expressed rhVEGF121 at the level up to 23% of the total proteins and the yield reached 68g/L. The optimized fermentation condition for recombinant E.coli enables high expression level of rhVEGF₁₂₁.