Abstract: To reveal the aerodynamic sensitivity and disaster-inducing mechanisms of icing on supercritical airfoils during the climb phase, a multi-parameter decoupled study was conducted on the NASA SC(2)-0714 airfoil using the FENSAP-ICE numerical simulation method, investigating the effects of angle of attack, liquid water content (LWC), median volumetric diameter (MVD), and freestream velocity. The results indicate that ice accretion alters the stall characteristics of the airfoil: leading-edge ice induces laminar separation bubbles on the upper surface and deteriorates the flow field topology, resulting in premature stall angle and a narrowed safe flight envelope during the climb phase. The aerodynamic performance exhibits a three-stage nonlinear response to MVD variations, characterized by "initial abrupt degradation—steady evolution—secondary abrupt degradation", with the 30～40 μm range identified as the critical transition interval. This interval coincides with the upper limit of airworthiness regulation Appendix C, revealing the physical basis for the demarcation between conventional icing and supercooled large droplet (SLD) conditions. The influence of freestream velocity demonstrates a saturation effect: the lift-to-drag ratio loss reaches 21.3% at low-speed conditions, while the degradation gradually diminishes as velocity increases. The effect of LWC on aerodynamic degradation exhibits a linear accumulation characteristic. Based on the numerical simulation results, an engineering prediction model for lift-to-drag ratio degradation was developed, which establishes a linear relationship between lift-to-drag ratio and LWC with a slope of -4.56 under baseline conditions. This study reveals the multi-parameter sensitivity patterns and physical mechanisms of icing on supercritical airfoils during the climb phase, providing theoretical support for the airworthiness design of aircraft anti-icing and de-icing systems.