Abstract: The operation safety of spacecraft in the space environment is threatened by the space debris. Any leakage thus caused must be detected and repaired in time. The acoustic leakage detection is based on the characteristics of the flow field and the sound field. In order to study the characteristics of the flow field and the sound field of spacecraft when the gas leakage occurs in orbit, fluid dynamics and sound field models of leakage are established through the LES model and the Lighthill theory. For leak holes of different apertures, the characteristics, the velocity distributions and the Mach number distributions are obtained. The results can provide some guidance for the early warning and the detection of the location of the spacecraft on-orbit leak.