A collocation method is used to study the influence of the interaction between dispersed particles on the effective AC conductivity of a suspension of charged particles in electrolyte solution. The study shows that the collocation method is very effective over a wide range of concentration of charged particles. The method is not restricted to the condition that the two phases of a suspension have the same dielectric constants, and, therefore, it provides an effective approach to a further study of macroscopic physical properties of a suspension of charged particles in electrolyte solution.