This paper is defined a class of ω—power context—free languages and the corresponding type of ω—pushdown automata．With the aid of ω—sequential transducer，some closure properties of ω—power context—free languages are discussed．The main result is that，for the class of ω—power context—free languages L，m(L)={s’(A)|A ∈L，S’is an ω—sequential transducer)一{h₂(h₁^-1(A)∩R)|A∈L，R is an ω—regular language，h₁ is a homomorphism and h2 is a λ—free homomorphism}．