Due to the presence of converter equipment in DC-fed AC systems, the modeling process for resonance analysis becomes more complex, making it challenging to simultaneously account for both the overall system behavior and the diversity of individual node component models. To address this, this paper proposes a method for analyzing system oscillation risk based on the s-domain nodal admittance matrix. First, from the nodal admittance matrix of the system’s power frequency equivalent circuit, a method is introduced to derive the system’s s-domain nodal admittance matrix after component equivalence simplification, and the system resonance modes are solved accordingly. Then, a sensitivity model is developed to assess the oscillation risk of AC component parameters under system resonance conditions. After simplifying the DC system, it is integrated into the AC system, and the sensitivity relationships among component parameters, network structure, and resonance modes within oscillatory frequency ranges are analyzed. Finally, an AC system model with DC feed-in is built on the PSCAD/EMTDC platform to verify the accuracy and effectiveness of the proposed component parameter sensitivity analysis method.