The synergy effect of konjac glucomannan(KGM) and κ-Carrageenan (KC) is one of an important research fields of polysaccharide interactions.The study of their interaction site can help to reveal many essential problem of the system, and it also plays a key role in the building and application of stable network system.The changes of KGM and KC blends rheological property in three ratios with microwave and heating process were studied , and their action sites were also measured through rheometer and molecular dynamics simulation, respectively. The results showed that the interaction between KGM and KC was changed after microwave treatment. The higher was the KC concentration, the better of their interaction. The hydrogen bonds between OSO₃ of KC and KGM molecular were the main forces to maintain the complex system stable, which indicated that the OSO₃ residue was the main KC and KGM interaction site. These results suggested that KC played a dominant role in KGM and KC composite system.