Abstract: In the present study,the Box-Behnken design and the method of response surface(RSM) analysis with 3 factors and 3 levels was employed to optimize the complexation conditions between Ulva pertusa polysaccharide and Zn²⁺,and investigate the effects of temperature,pH and weight ratio between Ulva pertusa polysaccharide and Zn²⁺ on the contents of zinc in polysaccharide-Zn.The results showed that the optimum conditions of Ulva pertusa polysaccharide complexation Zn²⁺ required temperature as 50℃,pH as 5.0,polysaccharide-Zn²⁺ weight ratio as 2.8:1,the concentration of Zn²⁺ as 3.00 mg/mL,and reaction time as 90 min.Under this condition,the contents of zinc in polysaccharide-Zn reached the maximum value as (102.41±0.67) mg/g.