The K-band (2.0–2.4 μm) is one of the most important wavebands for ground-based infrared observations, effectively penetrating interstellar dust and observing cool astrophysical objects and high-redshift galaxies. To address the long-standing gap and strong demand for near-infrared astronomical observations in China, this paper reports the astronomical observation results of a domestically developed mercury cadmium telluride (HgCdTe) infrared focal plane camera on the Sun Yat-sen University 80 cm infrared telescope. Located at the Lenghu Astronomical Observatory in Qinghai Province, the telescope is equipped with an HgCdTe infrared focal plane camera developed by the University of Science and Technology of China. Its chip is composed of three 640×512 HgCdTe infrared focal plane array detectors with a pixel pitch of 15 μm, developed by the Shanghai Institute of Technical Physics, Chinese Academy of Sciences. Test results show that the 5σ limiting magnitude is 15.3 mag (Vega system) in a single 20-second exposure, reaching the international level of the Two Micron All-Sky Survey (2MASS), with a photometric accuracy of up to 12 mmag for bright sources. After stacking for 30 minutes and 2 hours, the limiting magnitudes reach 17.5 mag and 18.2 mag, respectively. These results demonstrate that the system can conduct K-band time-domain astronomical observations at different detection depths and temporal resolutions. This achievement marks China ′s first successful astronomical K-band scientific imaging observation using a domestically developed HgCdTe infrared focal plane camera, providing a solid and reliable independent observation platform for infrared astronomy research in China.