A spectacle frame comprises a substantially straight or slightly curved structure composed of two rims and a bridge, and two temples. The bridge is connected between the two rims. One end of each temple is rotatably connected with an outward portion of a respective rim via a hinge. Each temple is formed into a bow-shaped bar that has a front portion, a middle portion, and a rear portion. The spectacle frame is designed to have a predetermined first parameter, a predetermined second parameter, a predetermined third parameter, and a predetermined fourth parameter, whereby the spectacle frame has a size smaller than general glasses to facilitate a person engaging a special task to wear a protective shield and prevent the protective shield from being interfered with, and can perfectly fit various facial profiles of persons so as to keep the protective shield airtight.