With the development of HgCdTe infrared focal plane arrays toward super-large sizes and small pixels, the requirements of blind pixel rate, especially continuous blind pixel and uniformity, are increasing. The surface defect has become an important factor to inhibit the application of Si-based HgCdTe molecular beam epitaxy (MBE). By solving three key problems of MBE-grown HgCdTe, namely, beam stability, beam measurement accuracy and growth temperature control stability, and by optimizing the growth parameters through orthogonal experiments, the defect density of Si-based HgCdTe materials is controlled within 500 cm^-2 and the optimal value is 57.83 cm^-2.