In this chapter, we present applications of abstract interpretation techniques in quantum computing. Quantum computing is a now well-established domain of computer science, and the recent developments of semantic techniques show the vitality of this rapidly growing area. On the other hand, the proof has been made that abstract interpretation is a powerful theory (of “classical” computer science) for comparing more or less precise semantics of the same programming language. In a more general picture, abstract interpretation can be seen as a framework for comparing the precision of several representations of the same dynamic system evolution. In this paper, we point out that abstract interpretation can be fruitfully used in quantum computing: (i) for establishing a hierarchy of quantum semantics and (ii) for analyzing entanglement evolution.