To address the problem of steering wheel shaking during idle operation of a certain extended-range vehicle model, the source-path-response analysis approach was adopted to identify the influential factors with significant contributions. Through optimization of powertrain system parameters, disconnection of suspension installation points, disturbance of the steering system, and disconnection of the exhaust system, etc., it was confirmed that the damping of the dual-mass flywheel and the dynamic stiffness of the rear suspension were the key components affecting the steering wheel vibration during idle charging operation. After the implementation of the optimization plan, the root mean square value (RSS) of the three-axis steering wheel vibration decreased from 0.031 g to below 0.017 g during idle operation. This achieved a non-perceptible vibration sensation in the steering wheel and improved the NVH quality of the entire vehicle.