An assembly structure for eyeglass lens is disclosed herein to include a one-piece lens and a frame. The frame has a connection portion in the middle thereof, from two sides of which two nose pads extend downwardly and obliquely in two opposite directions. The connection portion has a joining hole, and the lens further has a flexible snap-in element in the middle thereof for corresponding engagement with the join hole. In such a case, the lens can be easily and conveniently detachable from the frame by merely pressing the flexible snap-in element.