In order to improve the photostability of p-aminobenzoic acid as UV-B sunscreen agent, an electrostatic complex with sodium alginate was formed. The occurring of the complex formation was demonstrated by rheological analysis and by difference spectrophotometry. Photodegradation of PA-BA and PABA-alginate complex, resulting from irradiation by sunlamp, was examined by UV spectrophotometry. The complex showed a greater UV absorbance capacity and nearly overlapped photodecomposition rate in comparison with the original sunscreen agent.