An iterative radiative transfer code for computing the apparent reflectance in models of the oceanatmosphere system was described. Although the present code only adopted the scalar quantity to calculate the apparent reflectance, it has lots of advantages. Over ocean surface, reflectances include reflectance of whitecaps, reflectance of the sun glint and reflectance emerging from the water -leaving, which were accounted in this code. So the result of the apparent reflectance of the upwelling diffuse radiation at the top of the atmosphere over rough ocean surface was better. The results of the comparison between the new code with 6S code and Z.A.'s code in computing the apparent reflectance in the same condition are excellent agreeable.