The photoconductive antenna is a very important device in the terahertz region and is widely used in terahertz time-domain spectroscopy technology. This article uses the molecular beam epitaxy method to grow Be-doped InGaAs/InAlAs superlattice as light absorbing materials for 1 550 nm laser pumped photoconductive antenna for terahertz detection. The prepared materials have a sheet resistance greater than 10⁶ Ω/sq and an electron mobility of 216 cm²/（V?s）. The active mesa and electrode structure of the detection antenna are prepared using wet etching and magnetron sputtering processes， and the antenna chip is packaged on a PCB board. A detection antenna measurement system is built by employing a domestically produced 1 550 nm femtosecond pump laser， and the detection antennas with electrode gaps of 40 μm and 60 μm are characterized. The measurement results indicate that the 60 μm antenna has a wider spectral width and power dynamic range， reaching 4.0 THz and 77.0 dB， respectively.