Abstract. In this article we study the idea of complex neutrosophic subsemigroups. We define the Cartesian product of complex neutrosophic subsemigroups, give some examples and study some of its related results.We also define complex neutrosophic (left, right, interior) ideal in semigroup. Furthermore, we introduce the concept of characteristic function of complex neutrosophic sets, direct product of complex neutrosophic sets and study some results prove on its.