Abstract: ‍ ‍Compared with the traditional plane wave radar， the vortex electromagnetic wave radar echo contains more target micro-motion information. More accurate target micro-motion parameters can be obtained by comprehensive use of linear Doppler effect and angular Doppler effect. At present， the separation methods of linear Doppler signal and angular Doppler signal mostly use the image domain method to process the time-frequency image. However， the performance of these methods is limited by the time-frequency resolution， and the complex time-frequency curve separation problem needs to be solved. In order to solve the above problems， an angular Doppler signal separation method applied to the scene with small angular Doppler and unknown rotation center is proposed. Firstly， the Doppler effect of rotating target in single-frequency vortex electromagnetic wave radar is analyzed. Then the linear Doppler is used to obtain the radial micro-motion parameters of the rotating target， the reference signal is constructed to compensate the vortex electromagnetic echo， and the relatively pure angular Doppler is obtained by the filtering method. Finally， based on the compressed sensing algorithm and the property of angular Doppler of rotating target， the comprehensive micro-motion parameters of rotating target are obtained. The correctness and robustness of the proposed method are verified by simulations， and the performance of the proposed method is also analyzed.