Abstract
It is clear that all kinds of dictionaries have always been shaped by what lexicography is “a domain where” linguistic insights can be regarded as “applied lexicology”.Systemic Functional linguistics,which studies language from the advantage point of meaning and purpose,with its emphasis on the study of language in use,has much to offer to lexicographers,in both theory and practice.We know that the scope of lexicography is very wide.Therefore,the author will discuss the insights that may be gained from SFL in English idioms.