A differential duplex filtering antenna with low cross-polarization is introduced in this paper. The duplex antenna consists of a radiation patch, two coupling slots and a feed filtering network. Transmitting signals pass through the feed filtering network, and then the antenna is excited by two coupling slots symmetrically etched on the ground plane. Receiving signals are received by the radiation patch, and then pass through the feed filtering network. Simulation results show that the maximum gain of the antenna is 5.86 dBi in the low frequency band (1.95 GHz-2.050 GHz) and 6.67 dBi in the high frequency band (2.38 GHz-2.51 GHz). In addition, symmetrical radiation patterns and low cross-polarization are also achieved because of the differential-feed structure.