To address the mission requirements of microwave over-the-horizon radar for detecting long-range maritime targets, a design method, radiation pattern simulation, structural implementation, and test results of an X-band parabolic cylinder array antenna are introduced. Comprising 256 parabolic cylinder boxes, the array antenna is characterized by a large aperture and high cost-effectiveness, achieving 47 dB antenna gains with a scanning angle of ±40°. It demonstrates promising application prospects in phased array radar antennas.