In order to meet the needs of integrated and multi-functional RF front-end devices, a planar filter patch antenna with controllable radiation nulls is designed for WLAN 5 GHz band. The antenna is based on a microstrip patch antenna fed by a coaxial probe. The upper surface is a metal radiation patch fused with a ribbon and a rectangular slot, and the lower surface is trial-grounded.The symbiotic strip is located on both sides of the wide edge of the radiation patch, and the rectangular groove is etched on the radiation patch and located on both sides of the coaxial feed point. The two structures introduce a radiation null at the low frequency and high frequency of the passband respectively, which makes the antenna realize the filter response and good radiation characteristics. At the same time, the position of the two radiation nulls is freely controllable, which improves the flexibility of the design. The simulation and test results show that the center frequency of the filter antenna is 5.25 GHz, the relative bandwidth is 14% (4.89~5.62 GHz), and the two radiation zeros are located at 4.55 and 6.05 GHz respectively. The average gain in the working passband is about 7 dBi, and the out-of-band suppression level is greater than 19 dBi. The test results are consistent with the simulation results. The design of the filter antenna does not introduce additional filter network, saves the overall size of the antenna, and has low profile, light weight, compact structure, and good filtering and radiation performance.