A soluble tumor necrosis factor receptor 2 (TNFRII) mutant has an amino acidsubstitutionat position 92Glu compared with the wild TNFRII. The mutant improves thecytotoxicitycapacity of neutralizing TNFalpha and lymphotoxin. The mutant and fusionprotein comprising itare useful for the treatment of TNFalpha and lymphotoxin related diseases.