Lycium barbarum and Ganoderma lucidum, highly valued Chinese medicinal fruit and mushroom, have attracted more and more attention because of the antitumour activities they have shown, and polysaccharides are considered their most important functional constituent. Forming new compounds of L. barbarum polysaccharides, isolated from dried L. barbarum fruits, and G. lucidum polysaccharides, derived from a submerged culture of G. lucidum, has been investigated in this paper. Our data illustrate that two polysaccharide compounds, fermented polysaccharides and mixed polysaccharides, at the appropriate ratio and concentration have stronger free radical scavenging ability than the single polysaccharide. Ion exchange chromatography and high-performance liquid chromatography (HPLC) analyses indicated that the components of the new polysaccharide compounds had changed compared to those of the single polysaccharide. In addition, similar fractions were shared with the two polysaccharide compounds. Hence, the findings demonstrate that these new polysaccharide compounds might have stronger bioactivity than a single polysaccharide and could be obtained more easily by fermentation.