Currently, the synthesis of polysaccharide metal ion complex is predominantly categorized into three approaches: chemical synthesis, physical synthesis and biosynthesis method. According to research, polysaccharide metal ion complexes usually exhibit superior biological activities than metal ions or polysaccharides alone, including antioxidant, hypoglycemic, hypolipidemic, immune regulation, anti-tumor, anti-inflammatory and antibacterial activities. In this paper, the preparation process, biological activity and structural characteristics of polysaccharide metal ion complexes were reviewed, aiming to provide references for the development of new therapeutic drugs and adjuvants. And the complexation of Tremella fuciformis polysaccharides and metal ions was prospected.