Modern British English words could be analyzed and studied, diachronically or synchronically, from different branches or schools of linguistics or from different disciplines. Phonologically, the analysis and study of Modern British English words are mainly on their pronunciations, syllabifications and word stresses, which were studied broadly and deeply by the predecessors who had fruitful research achievements and rich research experiences. And confined by social and historical reasons, their research still need to be further analyzed to make a supplement or an improvement. A Multi-Dimensional Model of Modern British English Phonology (MD Model of Modern BrE Phonology for short) which carries forward the former and present research achievements and experiences, and draws the theoretical framework of Optimality Theory, and combines historical linguistics and etymology in it. It is hypothesized as the approach of this thesis to explain pronunciations, syllabifications and word stresses in Modern British English which could not be settled in the theoretical framework of OT alone.