A method for forming a light sensing device is provided. The method includes forming a light sensing region in a semiconductor substrate and forming a light shielding layer over the semiconductor substrate. The method also includes forming a dielectric layer over the light shielding layer and partially removing the light shielding layer and the dielectric layer to form a light shielding element and a dielectric element. A top width of the light shielding element is greater than a bottom width of the dielectric element. The light shielding element and the dielectric element surround a recess, and the recess is aligned with the light sensing region. The method further includes forming a filter element in the recess.