A molding glass lens and a mold thereof are disclosed. The molding glass lens consists of an upper optical surface, a lower optical surface, two outers surrounding the optical surfaces and at least three grooves arranged in the form of a circle disposed on the lower outer and/or the upper outer. The disposition of the grooves has no affecting in original size of the outers as well as assembling with other mechanical parts in les group. The mold of the lens includes an upper molding unit and a lower molding unit. Cavity of each molding unit is composed of a central part for forming an optical surface of the lens and an outer circular part for forming outer of the lens. At least three protrudent parts with the same height are disposed in the form of a circle on the outer circular of the lower molding unit and/or the upper molding unit. Thus the air in the mold cavity is easy to exhaust through the gap formed by protrudent parts and glass preform. Therefore, air bubbles generated during the molding processes are prevented and precision of the glass lens is provided.