Firstly, the notion of fuzzy ultra ⊙-ideal is introduced and its properties are investigated in regular residuated lattices, and some equivalent characterizations of fuzzy ultra ⊙-ideals are obtained. Secondly, the lattice operations ∨, ∧ and the order-reversing involution on the set
FU(
L) of all fuzzy ultra ⊙-ideals in a regular residuated lattice
L are defined. It is proved that (
FU(
L),∨,∧,
,0
L,1
L) formes a De Morgan algebra if
L satisfies the condition (P). Finally, the adjoint pair (
) on
FU(
L) is defined. It is also proved that (
FU(
L),
,0
L,1
L) formes a residuated lattice if
L satisfies the condition (P).