High-quality npn medium-wave/medium-wave two-color HgCdTe materials were prepared by molecular beam epitaxy. Fourier transform infrared spectroscopy (FTIR), secondary ion mass spectroscopy (SIMS) and X-ray double-crystal diffractometer (XRD) were used to test the material composition, thickness, element distribution, average half-peak width and other parameters. The results show that the HgCdTe composition of the bottom n-type absorption layer is 0.318 with a thickness of 7.15 m, the composition of the p-type layer is 0.392 with a thickness of 2.47 m, and the composition of the top n-type absorption layer is 0.292 with a thickness of 4.71 m. The As doping concentration is about 3×1018 cm-3, the In doping concentration is 4×1015 cm-3, and the average half-peak width is about 95 arcsec, indicating that it has good quality. The surface defects of the HgCdTe epitaxial layer were characterized by focused ion beam (FIB), scanning electron microscope (SEM) and energy-dispersive X-ray spectrometer (EDX) tests. It is confirmed that the defects are mainly related to growth parameters such as growth temperature and Hg/Te beam-current ratio.