This paper provides a frame-based account of lexical polysemy exhibited in four commonly used words, viz. koan 2趕, thau 3透, tau 3鬥 and chio 3照, in Taiwanese. It aims at arguing that frame semantics can make up for the deficiency of traditional lexicographic works. 　　Sense extension as a source of lexical polysemy is reflected in various syntactic realizations and it can be demonstrated in the case under discussion as a result of the operation of metaphor and metonymy. In this paper conceptual frames are set up to capture in an economic way the semantic relatedness within each polysemous word. In-depth analyses of these four words are made to motivate frame semantics for dealing with the problems of lexical polysemy in Taiwanese.