An antenna structure and a modulation method therefor are provided. The antenna structure includes a radiation patch, a radio-frequency port, a first signal line, a second signal line, a power divider, and a first phase modulator. The radiation patch includes a first feed point and a second feed point. One end of the first signal line is connected to the first feed point. One end of the second signal line is connected to the second feed point. The power divider is separately connected to the radio-frequency port, the other end of the first signal line, and the other end of the second signal line, and is configured to allocate electromagnetic waves of the radio-frequency port to the first signal line and the second signal line; and the first phase modulator is configured to modulate the phase of the electromagnetic waves of the first signal line.