This invention provides an imaging optical lens assembly, in order from an object side to an image side comprising: a front lens group, an aperture stop and a rear lens group; wherein the front lens group comprises, in order from the object side to the image side: a first lens element with negative refractive power having a concave image-side surface; a second lens element with negative refractive power; a third lens element with positive refractive power and a fourth lens element with positive refractive power; wherein the rear lens group comprises, in order from the object side to the image side: a fifth lens element with positive refractive power; and a sixth lens element with negative refractive power; wherein the fifth lens element and the sixth lens element are connected to form a doublet. By such arrangement, sufficient field of view is provided, and the aberration of the lens assembly is corrected for obtaining high image resolution.