Abstract: Objective: To determine the effects of posture asymmetry which includes yaw rotation and roll rotation on the aerodynamic characteristics during flight in ski jumping. Methods: The athletes and skis were regarded as a multi-body system. By using partially averaged Navier-Stokes(PANS) turbulence model and numerical simulation of computational fluid dynamics(CFD),the aerodynamic characteristics during flight under different asymmetric postures were predicted. The calculation conditions of yaw rotation angle include 2.5°, 5.0°, 7.5°, 10.0°, 12.5° and 15.0°, and the calculation conditions of roll rotation angle include 2.5°, 5.0°,7.5°, 10.0°, 12.5° and 15.0°. Results: 1) Under the influence of yaw rotation or roll rotation, the yaw force, yaw moment and roll moment are obviously generated in the multi-body system, and the values all show a monotone increasing trend; 2) both yaw rotation and roll rotation have great influence on the lift, drag and pitch moment in the multi-body system. When yaw rotation angle is 15.0°, the total lift of the system decreases by 10.14 N, the total drag increases by 36.71 N, the total lift-to-drag ratio decreases by 0.439, and the value of pitch moment increases by 2.59 N·m. When roll rotation angle is 15.0°, the total lift of the system decreases by 51.82 N, the total drag decreases by 11.89 N, the total lift-to-drag ratio decreases by 0.204, and the value of pitch moment increases by 19.51 N·m. Conclusion: 1) The adverse effects of roll rotation are generally more significant than that of yaw rotation; 2) the multi-body system has a phenomena of yaw self-stability and roll self-stability, and a possible solution to maintain the stability of ski jumping flight under lateral wind can be proposed, i. e., by taking appropriate yaw rotation angle or(with) roll rotation angle to largely offset or even eliminate the adverse effects of lateral wind; 3) the influence mechanism of posture asymmetry on the aerodynamic characteristics during flight in ski jumping can provide effective auxiliary support for on-the-spot prediction and decision-making.