The present invention relates to an optical composition for blocking near-infrared rays, comprising a mixture of a polyurethane-based thermosetting resin composition and a near-infrared absorbent, andprovides an optical composition for blocking near-infrared rays, comprising: (1) at least one of polyisocyanate compounds in a liquid phase (I); (2) at least one of polyol or polythiol compounds in aliquid phase (II); and (3) a near-infrared absorbent having a high near-infrared absorbing ability of less than 5% in the range of 800-1000 nm, and to a method for manufacturing near-infrared blocking spectacle lens using the same. The spectacle lens obtained from the optical composition of the present invention can effectively prevent the damage to the retina by effectively blocking near-infrared rays.