Type Ⅳ silica glass is an important special glass material, which plays an important role in optical detection, inertial navigation and other fields. Optical homogeneity is an important way to characterize the structural homogeneity of optical glass, and the optical homogeneity of type Ⅳ silica glass is closely related to structural distribution consistency of silicon-oxygen network. In this paper, the radial distribution characteristics of hydroxyl, metal impurities and oxygen defects and the radial variations of silicon-oxygen bond angle were studied by four-step optical homogeneity test, ultraviolet-visible-near-infrared spectroscopy, infrared reflection spectroscopy, etc. And the influence of each affecting factor on optical homogeneity of sample was studied by correlation analysis. The results show that the wave aberrations t0Δn, which indicates the optical homogeneity of glass, decreases first and then increases along the glass radius. The radial distribution of hydroxyl is opposite to t0Δn radial variation as a whole. The radial variations of transmittance at 200 nm and silicon-oxygen bond angle are similar to t0Δn radial variation. The influence of hydroxyl on optical homogeneity of type Ⅳ silica glass is small, and the radial variations of metal impurities, oxygen defects and silicon-oxygen bond angle are the main factors affecting the optical homogeneity of type Ⅳ silica glass.