The degree of ionization of polyacrylic acid and pure sodium polyacrylate solutions covering a wide concentration range was deteremined by measuring the pH values of these solutions. The results show that the degrees of ionization are very sensitve to the location of the concentration range of polyelectrolyte solutions．The concept of dynamic contact concentration proposed by Qian Renyuan and the principle of division of flexible neutral polymer solutions into four concentration ranges namely extremely dilute

dilute

semidilute and concentrated solutions are confirmed to be universally applicable to polyelectrolyte solutions．