This paper presents a high-resolution, non-contact method for real-time torque measurement in rotating shafts, with torsional-angle and rotational-speed-related information recoverable from the encoded wavelength signals. The system integrates a differential dual-probe chromatic confocal configuration with helicoid-coded rings (HCRs) to convert torsional deformation into spectral displacement signals. A theoretical model is established to reveal the intrinsic relationship between measurement resolution, dynamic range, and shaft mechanical properties, including shear modulus and polar moment of inertia. Experimental results demonstrate excellent performance, achieving over 99% static torque linearity and a calibration RMSE of 1.21%. For a steel shaft (G = 76.92 GPa), the angular and torque resolutions reach 0.314 μrad and 0.0043 N·m, respectively. The proposed system features strong electromagnetic immunity, no onboard power requirement, and potential for multi-parameter information extraction during rotating operation. The system has significant potential not only for the health monitoring of drive shafts in rotating machinery but also for providing critical real-time torque feedback to optimize powertrain control in electric vehicles, aircraft, CNC machine tools, and industrial robotics.