An optical system for eyepieces was designed to meet the demand of a wide-angle head mounted display for the wide Field of View ( FOV) , high resolving power and compact , light-weight structure. Twelve groups of high quality eyepieces with a FOV of 33°×24° arraged in a 4×3 array were stitched in a single-eye optical system to realize the design with a wider FOV. The eyepiece was made up of a lens which contained a diffractive surface and an aspheric surface.The dispersion characteristics of binary optical elements were used to correct the chromatic aberration, and the aspheric surface was selected to correct the aberrations( spherical aberration,astigmatism, coma and distortion). Furthermore, an OLED micro-displayer was used to achieve compact and light-weight structure, and the field-of-viewing stitch was used to implement the wide field of view. Experiments show that obtained optical system can offer the horizontal FOV of 120° and the vertical FOV of 60°. Moreover, the resolving power is 43 pixel/degree,the MTF is higher than 0.1 at a spatial frequency of 30 lp/ mm across the entire visual field, and the maximum distortion is less than 3%. The optical system has perfect performance and can meet the domanial demands of virtual reality display and super-wide FOV.