The purpose of this study is to investigate how the morpheme "-sab-" is used in the contemporary Korean historical drama scenario. Since the "-sab-" is always used with a word(s) showing the meaning of politeness, its function is to express speaker's politeness. Especially, the politeness word is optionally used with the morpheme "-sab-" but the "-sab-" is always required to use with the politeness word. A grammatical principle to express the politeness is generally related to the speaker's intention. Although the "-sab-" does not exist in the sentence presenting the politeness, the sentence does not have any problem with the grammaticality. The "-sab-" is limitedly used in the addresseehonorifics scale. In the scale, the "-sab-" can be combined with 'ha-so-seo'(old polite level form), 'hap-syo'(new polite level form) and 'hae-yo' (semi-polite level form). This means that the addressee is not respected by the speaker as much as the speaker is supposed to express the politeness. The morpheme "-sab-" is used in forms of regular combination "-sa-ob-/-sa-o-" and "-ob-/-o-" which are phonologically conditioned allomorphs. Sometimes, the "-sab-" is also used in a irregular combination form, which seems to be historically fixed. (188)