To utilize modified pulp fibers in papermaking system, it is necessary to evaluate the interaction between modified fibers and papermaking additives. Fluorescent whitening agent (FWA) is an important additive which has been widely used for production of writing and printing paper. We modified pulp fiber surface by Layer-by-Layer multilayering of polyelectrolytes, and investigated the interaction between these fibers and FWA used in internal addition or surface treatment. Pulp fiber with cationic surface charge showed a good affinity to internal FWA. For FWA in surface sizing agent, whiteness and brightness of paper was dependent on pickup weight and polyelectrolyte type. Pulp fibers with C-starch/PSS multilayer showed better optical properties than poly-DADMAC/PSS treatment. It indicated that polyelectrolyte type in Layer-by-Layer multilayering as well as a good affinity to FWA is important to get better whiteness and brightness.