Abstract: TheR0-algebra, implication lattice and basic logic algebra are studied. The properties of a mixed operation ∶a b= (a→ b) in evaluation lattice, especially its properties inR0-algebra, are discussed. Akind of filter is derived by use of this mixed operation, with some interesting results being obtained. Thiswork can deliverreference and help forfurtherresearchonR0-algebra and evaluation lattice.