An shading area-controlled shift-frequency jamming method is presented for synthetic aperture radar (SAR). While the carrier frequency of the interference is stepped between pulse to pulse to generate the coupling effect between range and azimuth,an azimuth shift-frequency is added. The combination of them provides an area-controlled shading jamming. The unique of the jamming method is that the energy can only appear on the target that needs to be covered, so that less jamming energy is needed. Simulation results verify the analysis and its jamming effectiveness for SAR.