Abstract: ZSM5 zeolite is characterized by XRD, FTIR and acidbase titration in detail. The results show that the main sorption sites are =XNa, =YOH and =YO^- in all pH ranges. The sorption of Co²⁺ on ZSM-5 zeolite is strongly dependent on pH value and ionic strength under ambient conditions. The sorption edges of Co²⁺ on ZSM-5 zeolite in 0.01mol/L NaClO₄ is modeled using a quasi-mechanistic sorption model (1-site protolysis non electrostatic surface complexation and cation exchange (1-SPNE SC/CE) model). The Co²⁺ sorption edges could be modeled in the pH range about 3 to 7 using cation exchange reactions for Co²⁺/Na⁺ and three surface complexation reactions on the sorption sites forming =X₂Co, =YOCo⁺ and =YOHCo²⁺ complexes appear successively with increasing of pH values.