Aspergillus penicillioides as one of the main contaminating fungi in jet fuel has been identified. In order to study the influence of A. penicillioides on the the physicochemical properties of jet fuel, two BH-fuel system were established. Contrary to the control group, in the positive group the A. penicillioides has been cultivated. Then the physicochemical properties of the two system were compared after cultivation. And the result shows that the A. penicillioides will obviously affect the appearance, water separation index, particle size and acid of the jet fuel. On the contrary, freezing point, flash point, density and water reaction of jet fuel has no significant change. Meanwhile, A.penicillioides could lower the thermal oxidation stability of jet fuel while enhancing its corrosion.