Aiming at the problems of the current head-mounted display with large volume, large weight, and small field of view, in order to meet the user’s demand for light and small head-mounted displays, the Ranston eyepiece was used as the initial structure, and then was optimized by using ZEMAX software. Image quality evaluation and tolerance analysis were then carried out. The result shows that each channel in the binocular system uses only two lenses, the maximum field of view of the optical structure is 80°, the total length is 54.24mm, the maximum distortion is less than 4.7%, the weight of the two lenses is less than 11.5g. Compared with related research, the field angle and the number of pixels are increased, the volume is reduced, and the modulation transfer function is improved. The head-mounted display has certain market prospects, and can provide a reference for the optical design of the light and small head-mounted display.