Flock flight by birds or insects is a common phenomenon in nature. In order to investigate the interaction mechanism between the complex flow and aerodynamic characteristics between the wings of flocks of flying organisms, this paper numerically studies the lift and propulsive characteristics of tandem self-propelled flapping wings at different angles of attack (AoAs) and pitching amplitudes. It is found that the number of equilibrium states changes with different AoA. At the same AoA, the aerodynamic characteristics of the wings corresponding to different equilibrium states are significantly different. The possible numbers of equilibrium states gradually decrease with the increase of the AoA. And when the AoA increases to 15°, the final flight state of most of the cases is unstable. The aerodynamic characteristics of the fore wing do not change significantly as the pitching amplitude increases. With the influence of the hind wing, as the pitch amplitude increases to the maximum value, the lift of the system gradually increases to be comparable with that of the single wing, the lift efficiency and propulsion efficiency are higher than that of the single wing, and the power consumption is lower than that of the single wing. Therefore, by increasing the pitch amplitude it is possible to improve the lift characteristics of the tandem system while still maintaining good propulsive performance. These findings in this paper can provide some guidance for understanding the biological behavior of asymmetric flapping wing flight with tandem layout in nature.