In order to realize the remote sensing detection classification and identification of the rotor, the laser echo feature of extended rotor target based on micro-Doppler effect was studied. The micro-Doppler coherent laser echo model of moving extended rotor was built with the panel method of physical optics. Angular scattering characteristics of laser were analyzed and calculated, which proved that rotor had the same echo reflectivity everywhere under the far field condition. Laser detection echo of three typical rotor shapes was simulated, and the time-frequency features of extended rotor were achieved by Smooth Pseudo Wegener-Villy(SPWV) transform. The electromagnetic scattering mechanism confirms that each frequency band was related to the shape of the rotor, and the number of blades does not affect the expression of features of rotor shape in time-frequency figure as well as the moving velocity. The laser detection calculation methods of rotor shape parameters, including aspect ratio, root-tip ratio and sweep angle of rotor tip, were proposed and proved to be correct through simulation, which layed the foundation for rotor identification.