In this paper, a filtering patch antenna with flexibly controllable radiation nulls is presented. The patch antenna is fed by an F-shaped probe consisting of two arms along the Y-axis and a metal column along the Z-axis. A broadside radiation null on the lower band is generated by cross-coupling. Meanwhile, a folded defected ground structure (DGS) is introduced to generate an upper band radiation null. By adjusting the parameters of F-probe and DGS, two radiation nulls can be controlled independently to achieve great out-of-band suppression. For demonstration, a prototype is fabricated and measured. The simulation results agree well with the measured ones. A flat in-band realized gain of filtering antenna is about 7.1dBi. The proposed filtering antenna operating at 2.33 GHz achieves a wide relative bandwidth of 9.8% and out-of-band suppression level is more than 24dB.