An optical image capturing system is provided. In order from an object side to an image side, the optical image capturing system includes a first lens, a second lens, a third lens and a fourth lens. The first lens has a refractive power and the object side thereof may be convex. The second lens and the third lens have refractive power. The object side and the image side of the foregoing lenses may be aspheric. The fourth lens may have positive refractive power. The object side and the image side thereof are aspheric. At least one of surfaces of the fourth lens may have one inflection point. The four lenses have refractive power. When meeting some certain conditions, the optical image capturing system may have outstanding light-gathering ability and an adjustment ability about the optical path in order to elevate the image quality.