In this thesis, the conformance of Computer-Aided Translation (CAT) tools to TMX 1.4b and to the metadata of TMX 1.4b was investigated; correspondingly, the basic support and the advanced support of CAT tools to TMX 1.4b and its metadata were analyzed.Five CAT tools (Trados, MemoQ, Wordfast Pro, OmegaT and Matecat) were chosen to implement the conformance testing to test the level of the basic support and the advanced support of CAT tools to TMX 1.4b and its metadata.Through the conformance testing, we found out that CAT tools were fully conformant to TMX 1.4b while they were not fully conformant to the metadata of TMX 1.4b.Therefore, there is still a potential to improve the advanced support of CAT tools to the metadata of TMX 1.4b.