Let (S, •) be a semigroup and m be a σ-algebra on S. We say (S, •, m) is a measurable semigroup if π : S × S −→ S by π(x, y) = x • y is a measurable function. In this paper , we consider to m β as the collection of all ultrafilters on m. We show that m β is a compact right topological semigroup respect to generated topology by σ-algebra m on m β . Also we study some elementary properties of the algebraic structure of m β .