Abstract: In this paper, a mathematical model is presented for studying on the stability of compressible liquid jet in a coaxial swirling compressible airstream. The mathematical model and its solving method are verified by the data in literature, and the influences of compressibility, swirling gas and supercavitation on the stability of liquid jet are investigated, respectively. The results show that compressibility plays an important role in the instability of liquid jet. The range of wave numbers, the drop distributions and the drop diameters are changed due to compressibility. The effects of swirling gas on the stability of liquid jet are different in various disturbance modes. However, gas swirling has little impact on drop diameters. It is also found that the liquid jet becomes more unstable due to the greater supercavitating condition. Supercavitation with a small void fraction gets the greater wave numbers and the smaller drop diameters, while it draws different conclusion when void fraction reaches a certain value.