In order to study the shedding mechanism of non-cylindrical liquid flow with bow cross-section injected from one side of a cylindrical hole in cross-flow,a method combining CLSVOF multiphase flow model with large eddy simulation (LES) model was used to simulate the shedding process of non cylindrical liquid flow.The results show that the shedding phenomenon of non cylindrical liquid flow in cross-flow is caused by the surface wave formed by the Rayleigh-Taylor（R-T）instability because of the gas-liquid density difference on the windward surface and the K-H (Kelvin-Helmholtz) instability because of the gas-liquid velocity difference on the edge of the liquid flow.The continuous vortex generated at the outside edge of the liquid flow also promotes the shedding of the liquid flow.When the transverse airflow velocity increases,the shedding of liquid flow increases due to the increase of surface wave.When the transverse airflow direction changes,he shedding of liquid flow decreases due to the decrease of surface wave on the windward side.It is shown that the instability surface wave formed on the windward surface is the main factor causing the shedding phenomenon.