Saussure attaches great importance to linguistic units though he has not clearly presented us what they are.After an overall view of his linguistic theories,we think that he has summarized the nature of the units,i.e.they are identity,dual,system and ready-made in nature.On this basis,Saussure wisely distinguishes between units in vocabulary and units in grammar,with the former including words and ready-made phrases and the latter including patterns for word,phrase and sentence formation.Furthermore,Saussure thinks that the abstract units(units in grammar) are of more significance.