| In order to clarify the lift mechanism of downstream cylinder at a high Reynolds number Re=1.4×105, the large eddy simulation (LES) method was adopted to investigate the aerodynamic forces and flow pattern of two staggered circular cylinders. The ratio of center to center pitch (P) to the diameter of cylinder(D) is 4 and the incidence angle is 0° to 90°. The mean and fluctuating lift mechanisms of downstream cylinder were discussed as well. With the incidence angle increasing, the flow pattern of two cylinders is classified into the vortex impinging flow pattern, the vortex impinging and shear layer interaction flow pattern, the shear layer interaction flow pattern and the wake interaction flow pattern. For the vortex impinging flow pattern, the vortex impinging and shear layer interaction flow pattern, the vortex of upstream cylinder impacts with downstream cylinder, hence the downstream cylinder experiences a higher fluctuating lift than the single cylinder. For the shear layer interaction flow pattern, the downstream cylinder is subject to a significant mean lift, which is ascribed to the combined effects of two factors, i.e., the shift of stagnation point, and the interaction between the vortex of the upstream cylinder and the shear layer or vortex of the downstream cylinder.