The interaction between sodium dodecylbenezen sulfonate(SDBS) and Poly(ethylene oxide) (PEO) has been studied,' using surface tension and dye solubilization to determine the critical micelle concentration(CMC) without PEO, the critical aggregate concentration(cac) and polymer saturation concentration(c2) in the presence of PEO. The structure of surfactant-polymer complexes is analyzed by ESR and UV-vis spectra. For SDBS-PEO system, the result indicates that ptoymer-surfactant complexes have a more “ open” structure than the ordinary micelles. The polymer molecules may penetrate into the palisade of the micelles. Polyacrylamide(PAm) molecules remain in bulk solution as free molecules, and do not interact with SDBS.