Abstract: Millimeter-wave dual-polarized antennas have been widely used in high-speed, large-capacity wireless communications and high-precision radar systems due to their high operating frequency and excellent polarization compatibility. Coupling reduction between the dual-polarized ports is a key topic in this research area. However, due to space constraints, introducing additional decoupling structures is not only difficult to implement, but also degrades the antenna’s radiation performance. This study presents a novel decoupling strategy that includes an additional coupling channel, and the total coupling will be effectively reduced by manipulating the electromagnetic relationship between the additional and original couplings. The proposed method can significantly reduce coupling without requiring separate decoupling structures, while preserving the antenna’s radiation features. An antenna example developed on this method shows a good decoupling performance, with a −20 dB decoupling bandwidth of 9.14% and a coupling reduction of 5.1 dB to 41.2 dB in this band, verifying the proposed method.