Strain 51-43 was isolated using olive oil as sole carbon source in enrichment culture, while Rhodamine B as indicator from rich oil soil around Shanghai city. Strain 51-43 was identified as Aspergillus niger according to morphological observation and the partial 18S rDNA sequence analysis. The fermentation conditions of Aspergillus niger 51-43 lipase were optimized through the single factor and the orthogonal experiments. The optimal fermentation medium was composed of 2.35%peptone, 1%wheat flour, 0.1% K₂HPO₄, 0.05% MgSO₄·7H₂O, 0.01% CaCl₂, 1% NH₄Cl, 0.5% Tween-80 and 1% olive oil, pH 7.0. Under the fermentation condition of 28 ℃, 160 r/min, 72 h, the lipase activity could reach 19.28 U/mL，which was 2.21 times the original culture medium.