The reaction of poly(ethylene glycol) (PEG, number-average molecular weight M-n = 400-2000) and dimethyl 5-sulfoisophthalate sodium salt (SIPM) synthesized a series of anionic polymeric surfactants having a range of molecular weights. H-1-NMR, FTIR, and elemental analysis were employed to characterize the structures of these compounds. Also, the influences of the PEG segment lengths of PEG/SIPM copolymers on the surface tension, foaming properties, wetting power, and dispersant properties were investigated. The experimental results indicated that the solution that contained the PEG/SIPM copolymer surfactants exhibited excellent surface-active properties.