This paper deals with the productivity and constraint which take place in morphology and lexicon, and also explores the relationship between two modules. Many words or compounds are made by affixation and compounding. As a result of word formation processes, possible or actual forms appear in the morphology and the lexicon. However, we need a kind of device to restrict a power of word formation. So many kinds of constraint or condition play an important role in distinguishing grammatical or acceptable forms from ungrammatical or unacceptable ones. These grammatical or acceptable forms are stored in the lexicon.