In the process of development of transport aircraft, we often learn from the design experience of existing models for reference, which accelerates the development process but inevitably causes limitations. Taking a certain type of transport aircraft refuel system as an example, this paper calculates the influence of different refueling pressure, calculation step, shut-off interval, and mode on the probability of shut-off refueling simultaneously in multiple tanks under the condition off three-tank layout. The results show that the probability of three tanks shut-off at the same time of transport aircraft is basically zero, while the probability of multiple tanks shut-off simultaneously generally does not exceed 2%, and this value does not exceed 3% under special scenes. This value shows a further downward trend with the decrease of the calculation step and shut-off interval definition. The probability of multiple tanks shut-off in automatic model is lower than that in manual refueling mode. In the actual refueling situation of transport aircraft, it is quite difficult to have the scene of three fuel tanks being refueled and shut off at the same time, and the probability of two fuel tanks being shut off at the same time is also very low. In addition, the analytical ideas and methods formed by the research also have certain reference for the design of refueling system for other transport aircraft.