An antenna structure includes a main antenna, a parasitic antenna, a matching circuit and a switching circuit. The main antenna includes a feeding strip and a first radiating strip coupled to the feeding strip. The parasitic antenna includes a grounding strip and a second radiating strip coupled to the grounding strip. The second radiating strip is positioned adjacent to and apart from the first radiating strip, and further configured to electromagnetically couple to and be parasitically fed by the first radiating strip. The parasitic antenna and main antenna cooperatively generate at least one high-frequency resonate mode and a low-frequency resonate mode. The matching circuit is electronically coupled to the feeding strip. The switching circuit is electronically coupled to the matching circuit, and configured to regulate an inductance value of the matching circuit output to the feeding strip, thereby regulating a central frequency of the low-frequency resonate mode.