The colloid-colloid structure factor is calculated for polystyrene colloid solutions on the basis of the charged-hard-sphere (CHS) model in the rescaled-mean-spherical-approximation (RMSA). It is shown that the characteristic features of the experimental structure factors can be well reproduced by a binary CHS system for a salt free solution and by a quaternary CHS system for the solution with added salt. The physical meanings of the large effective hardsphere diameter and the reduced effective charge obtained by the rescaling procedure are discussed.