Mechanism of splitting and atomization of compressible viscous 。ular jet was studied with linear stability theory. The dispersion equation for disturbance development of liquid jet surface in space mode was obtained and verified. It shows that the influence of liquid compressibility on instability of liquid jet is very small. With the increase of Mach number of liquid, the maximum growth rate of disturbance wave is basically unchanged. Effect of gas compressibility on jet stability increases with the increase of gas Mach number. With the increase of Reynolds number and Weber number, the effect of viscous force and surface tension on jet stability decreases gradually. With the increase of gas-liquid density ratio, the effect of aerodynamic force on jet stability is basically unchanged.