Abstract: In order to increase the yield of pectin esterase,the medium compositon and culture conditons were studied for fermentation of Aspergillus tubingensis CICC 2651.Resulted in biomass and pectin esterase activity,the optimal medium compostion was composed of high-ester pectin 3%,ammonium sulfate 0.5%,Na₂SO₄ 0.04%,MgSO₄·7H₂O 0.04%,K₂HPO₄ 0.2%,culture temperature 30℃,initial pH4.5,inculation volume 5%,liquid volume 40 mL. Compared to the basic technical contidtions,the enzyme activity at the optimum technique reached 1.53±0.09 U/mL,and increased by 1.79-fold. Under the optimum fermentation process,the production capability of pectin esterase by Aspergillus tubingensis CICC 2651 was significantly improved.