A lens structure of safety glasses consists of a lens part, and a warning sticker; the lens part consists of a main body, and a rim formed on a border of the main body; the rim has a strip-shaped recess on an upper portion, extending along an upper border thereof; the warning sticker is nontoxic, and contains no harmful substance, and it is stuck on the strip-shaped recess of the rim therefore the warning sticker won't stick out from the rim, and it is impossible for the warning sticker to be subjected to pulling force and fall off.