ABSTRACT With the information integration and intelligent embedding of Additive Manufacturing (AM) in intelligent industrial system applications, the information interoperability and knowledge discovery are becoming an infrangible trend that provide efficient data and knowledge-driven approaches for intelligent AM supports. STEP-NC standards in the specific AM digital thread are recognized as a potential means that can be used to explore multi-source data and knowledge analysis to support AM information exchange and knowledge discovery. As a comprehensive review of the related literatures, AM digital thread has deeply been discussed to analyse the information exchange and knowledge discovery for STEP-NC implementations. Furthermore, the STEP-NC for CNC has been reviewed to extend the possibility of STEP-NC for AM with ontology-based knowledge discovery by loads of literatures. In order to deeply explore the integration of STEP-compliant data transfer and knowledge discovery, ontology-based modelling approach and STEP-NC data transfer can be further discussed by combining the application of OntoSTEP-NC to review the literatures of data and knowledge-driven AM supports.