An Active XML (AXML for short) document is an XML document where some of the data is given explicitly while other parts are defined only intentionally by means of em- bedded calls to Web services. When one of these calls is invoked, its results will be returned to enrich the original document. AXML schema defines the specification that AXML doc- uments should conform. Containment checking for AXML schemas has many applications, and is thus important. In this paper, we focus on the problem of AXML schema con- tainment and propose an efficient algorithm for this purpose based on tree automata theory. More precisely, we extend regular tree automata to represent AXML schemas and re- duce schema containment to the corresponding problem of tree automata. Though the latter has high complexity in general cases, we describe the tractable case by introduc- ing un-ambiguous restricts to AXML schema. Finally, we discuss that our methods for checking schema containment also can be used to solve the problem of AXML schema rewriting.