An imaging lens assembly comprises a fixing diaphragm and an optical set including five lenses. An arranging order from an object side to an image side is: a first lens; the fixing diaphragm; a second lens; a third lens; a fourth lens; and a fifth lens. At least one surface of the five lenses is aspheric. By the concatenation between the lenses and the adapted curvature radius, thickness/interval, refractivity, and Abbe numbers, the assembly attains a big diaphragm with wide-angle, a shorter height, and a better optical aberration.