Wideband inverse synthetic aperture radar imaging of targets with rotating components suffers from severe defocusing due to high-order nonlinear phase modulation and range cell migration (RCM). To address this problem, a wideband subband fusion single-range Doppler interferometry (WSF-SRDI) framework is proposed. The wideband echo is first partitioned into multipe narrowband subbands via a polyphase filter bank. A theoretical constraint relating the subband number to RCM confinement is derived, ensuring that the RCM remains within a single range cell per subband. Within each subband, a SRDI path-integral model is then constructed to simultaneously achieve subband imaging and rotation parameter estimation, followed by a subband fusion process to enhance the overall image quality. Finally, utilizing the estimated parameters, the rotating components are reconstructed and suppressed through least squares estimation, yielding a well-focused image of the stationary main body. Simulation results and contrast analysis demonstrate that the WSF-SRDI maintains robust performance under low signal-to-noise ratio conditions. The proposed strategy provides an efficient solution for ISAR imaging of complex targets with multiple motion components.