An optical lens system for taking image has, in order from the object side to the image side: a positive first lens element with a convex object-side surface; a negative plastic second lens element with a concave object-side surface; a negative plastic third lens element with a concave object-side surface; a positive fourth lens element with a concave image-side surface; and an aperture stop located between an object to be photographed and the second lens element. The second lens element is provided with at least one aspheric surface, the third lens element is provided with at least one aspheric surface, and the fourth lens element is formed with inflection points. An on-axis distance between the first and second lens elements is T12, a focal length of the optical lens system for taking image is f, they satisfy the relation: (T12/f)*100>0.7.