In aqueous solutions

orderly polyelectrolyte-surfactant complex precipitates can been formed through electrostatic interaction．During complexing process

the conductivity of polyelectrolyte aqueous solution increases with adding of surfactant because of release of small inorganic electrolyte ions which have high conductivity. When polyelectrolyte and surfactant react according to equivalence and their concentrations are lower

the conductivity is distinctly turned．So the conductometric titration method can be used for measuring the composition of water-soluble copolymer containing ion monomer through complex reaction between polyelectrolyte and surfactant．In this investigation

the composition of copolymer P(AM-co-NaAMPS) of acrylamide (AM) and 2-acrylamido-2-methyl-propanesulfonate sodium (NaAMPS) has been determined with the aqueous solution of cetyl trimethyl ammonium bromide (CTAB) as titrant at a concentration of 0.001 mol·L-1 by conductometric titration method．The results obtained were compared with the results of element analysis

and were very satisfactory．It can be expected that the contents of ionic groups in water-soluble macromolecules can all be measured by using above complex reaction conductometric titration method．