[Objective] To identify marine fungus HN4-13 isolated from Lianyungang coastal sea sediments with antibacterial activity and to optimize the fermentation conditions of synthesizing antibacterial active substances. [Methods] Strain HN4-13 was identified based on its morphological characters and internal transcribed spacer (ITS) sequence; The optimization of fermentation conditions for antibacterial production by strain HN4-13 were investigated by the one-factor-at-a-time method and the orthogonal design method. [Results] Strain HN4-13 was identified as Aspergillus flavipes, and the optimal fermentation conditions can be recognized as follows: 4% sucrose, 0.5% peptone, 0.1% KCl, 0.06% NaH2PO4, 1% inoculation concentration, 28 °C, 160 r/min for 9 days. [Conclusion] The results provide the clues for further separation and purification of the antibacterial active metabolites derived from strain HN4-13.