A method for analyzing effect of sub-band interference on imaging performance in synthetic aperture radar, characterized in that, the method comprises: step S1: establishing a range impulse response model for sub-band signals with interference after being synthesized, to acquire information the about effect of the sub-band interference on the imaging performance; step S2: performing sub-band synthesis simulation on the sub-band signals with interference using the range impulse response model, to acquire a simulation result for verifying validity of the range impulse response model and for establishing a curve of a sub-band overlap ratio versus an amplitude of a false target; and step S3: simulating multi-sub-band Multiple-Input Multiple-Output, MIMO, data to be measured by multi-sub-band Single-Input Single-Output, SISO, measured data, and imaging the simulated multi-sub-band MIMO data to be measured to verify information about the effect of the sub-band interference on the imaging performance of the simulated multi-sub-band MIMO data to be measured, wherein the performing the sub-band synthesis simulation comprises: step S21: creating baseband pulse signals with interference in two sub-bands according to Gibbs' effect of signal spectrum; step S22: performing sub-band synthesis on the baseband pulse signals in two sub-bands and detecting the false target in the sub-band synthesized signal, to acquire an amplitude of the false target; step S23: changing the sub-band bandwidth and spectra overlap ratio of the baseband pulse signals in two sub-bands, to acquire the amplitudes of the false target at different bandwidths and different overlap ratios; and step S24: plotting the curve of the amplitude of the false target versus the spectra overlap ratio, the curve showing that the larger the sub-band width is, the smaller the amplitude of the false target caused by Gibbs's effect is; the greater the overlap ratio of the sub-band spectra is, the larger the amplitude of the false target is, and thus the acquired amplitude of the false target is closer to the amplitude of the false target in the impulse response model. step S1: establishing a range impulse response model for sub-band signals with interference after being synthesized, to acquire information the about effect of the sub-band interference on the imaging performance; step S2: performing sub-band synthesis simulation on the sub-band signals with interference using the range impulse response model, to acquire a simulation result for verifying validity of the range impulse response model and for establishing a curve of a sub-band overlap ratio versus an amplitude of a false target; and step S3: simulating multi-sub-band Multiple-Input Multiple-Output, MIMO, data to be measured by multi-sub-band Single-Input Single-Output, SISO, measured data, and imaging the simulated multi-sub-band MIMO data to be measured to verify information about the effect of the sub-band interference on the imaging performance of the simulated multi-sub-band MIMO data to be measured, step S21: creating baseband pulse signals with interference in two sub-bands according to Gibbs' effect of signal spectrum; step S22: performing sub-band synthesis on the baseband pulse signals in two sub-bands and detecting the false target in the sub-band synthesized signal, to acquire an amplitude of the false target; step S23: changing the sub-band bandwidth and spectra overlap ratio of the baseband pulse signals in two sub-bands, to acquire the amplitudes of the false target at different bandwidths and different overlap ratios; and step S24: plotting the curve of the amplitude of the false target versus the spectra overlap ratio, the curve showing that the larger the sub-band width is, the smaller the amplitude of the false target caused by Gibbs's effect is; the greater the overlap ratio of the sub-band spectra is, the larger the amplitude of the false target is, and thus the acquired amplitude of the false target is closer to the amplitude of the false target in the impulse response model.