In a method and device for side-band suppression, a positive eddy current correction factor and negative eddy current correction factor are determined and scanning N/2 times by a positive gradient takes place, and the positive gradient scanning signal is collected during each scan. Scanning N/2 times by a negative gradient also takes place, and the negative gradient scanning signal is collected during each scan. N is an even number. An eddy current correction of the N/2 positive gradient scanning signals collected according to the positive eddy current correction factor is performed as an eddy current correction of the N/2 negative gradient scanning signals collected according to the negative eddy current correction factor. The side-band suppressed spectrum signal according to the N/2 positive gradient scanning signals that have undergone the eddy current correction is calculated, as is the N/2 negative gradient scanning signals that have undergone the eddy current correction. The method and device according to the present invention can effectively suppress the side band.