The invention relates to a filtering antenna realization method capable of suppressing mutual coupling between channels based on cross-coupling. In an array antenna having more than two channels, inherent cross-coupling which is generated due to near field coupling or surface waves and exists between a plurality of adjacent or spatially near channels can be decoupled through cross-channel cross-coupling carried out in array antenna design. With the method adopted, the suppression of forward or (and) backward mutual coupling between the channels of a filtering antenna can be realized with no additional decoupling networks adopted. The method has the advantages of no need for extra area, no introduction of extra loss, flexibility in design and implementation, high degree of freedom of largeparameters and the like, and can be applied to a microwave millimeter wave filter antenna array system.