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 1550 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 cm}2^{/(Vs); 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 1550 nm femtosecond pump laser, and the detection antennas with electrode gaps of 40 μm and 60 μm were 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.