Electromagnetic vortex radar, with its characteristics of carrying orbital angular momentum and spiral phase wavefront, provides a new method for achieving super-resolution radar imaging. This paper combines the characteristics of vortex electromagnetic waves with the downward-looking electromagnetic vortex SAR imaging model to conduct in-depth research and analysis of SAR imaging technology based on vortex electromagnetic waves. We design corresponding imaging models, derive the imaging echo formula, and propose a novel three-dimensional ω K imaging algorithm based on fractional orbital angular momentum (OAM), specifically targeting multiple scattering targets. The three-dimensional Omega-K imaging algorithm compresses the distance by exploiting the relationship between azimuth terms in the slow time domain to obtain the azimuth information of the target; then, by combining the two-dimensional azimuth-range imaging information, the two-dimensional azimuth-range-elevation imaging information, and the elevation information of the target, the height information of the target is determined; finally, the three-dimensional imaging of the target is completed based on the Cartesian coordinate relationship. Through experimental simulation, this paper verifies the effectiveness of the proposed imaging algorithm and successfully achieves three-dimensional imaging of point targets.