Due to the growing demand for large-scale silicon-based HgCdTe materials for large-scale HgCdTe infrared focal plane detectors, the surface macroscopic defect density of 6-in short-wave silicon-based HgCdTe materials based on molecular beam epitaxy (MBE) is studied. The surface defects of the materials are analyzed using scanning electron microscopy (SEM), and the types of defects and their causes are determined. The composition uniformity of the materials is improved by improving the uniformity of the epitaxial temperature zone, the beam uniformity, and the stability of the source furnace. The preparation technology of 6-in short-wave silicon-based HgCdTe materials based on molecular beam epitaxy is improved by controlling the surface defects of the materials and optimizing the material process parameters, and high-quality 6-in short-wave silicon-based HgCdTe materials with high uniformity and low surface defect density are mass-produced. The results show that the composition difference between the center and the edge of the material is less than or equal to 3.0%, and the surface macroscopic defect (larger than 2 μm) density is less than or equal to 70 cm^-2.