This paper examines the lexical difference between Malaysia Hokkien and Taiwan Min-nan dialects, through a horizontal comparison between monochronic systems of these two dialects. According to our analysis, the lexical difference is mainly caused by the different social and lingual backgrounds of these two dialects, that is, the absorption of external elements through language contacts with different foreign languages. This also explains the major difference between the two dialects being that of borrowed words each from different foreign languages. In addition to this, Malaysia Chinese community being a multi-dialectal society, the interaction between different dialects definitely result in borrowed words among them, hence this is one important feature of Malaysia Hokkien lexicon, as compared to Taiwan Min-nan.