Thermocapillary-buoyant convection in an annular two-layer system under various gravity levels is investigated,in which the level set method is employed to capture the interface,and the continuum surface force tension model is used to simulate the Marangoni effect.The results show that,under the influence of the Marangoni effect,the interface bulges out near the outer wall and bulges in near the inner wall.The flow pattern consists of static convective cells,but a transition of flow pattern occurs as the gravity level increases.The interface deformability decreases with increasing gravity level,and the change rate of deformability is the largest as the gravity level varies from 0.001g to 0.01g.