The present disclosure provides an antenna system, including a circuit board and three antenna arrays. The circuit board includes a circuit chip and a first PCB, a first FPC, a second PCB, a second FPC, and a third PCB that are sequentially stacked and electrically connected to each other. The first FPC includes a first extension portion, the second FPC includes a second extension portion and a third extension portion on two adjacent sides, the first extension portion and the second extension portion are located on a same side of the circuit board, and every two of the first extension portion, the second extension portion, and the third extension portion are perpendicular to each other. The present invention further provides a communication terminal using the antenna system. The antenna system and the communication terminal of the present disclosure have a wide frequency band, high coverage efficiency, and a stable signal.