In Korean adjectival sentences, Experiencers and posssesors which are expected to be grammatical subjects generally appear to be these four cases. First, it appears as single nominative case, which is most general one. Second, it appears as dative and there is other argument which appears as nominative case. we call this case as dative subject construction. Third, it appears as nominative and there is other argument which appears as nominative case. we call this case as double subject construction. Fourth, there is a case which is convertible relation between dative subject and double subject constructions. In this study, we examine the fourth case, which shows the argument alternation of convertible relation between dative subject and double subject constructions. By the hierarchy among the semantic roles and various syntactic criterion, we find that the true subject is argument whose semantic role is experiencer or possesor. Also, theses don`t show unergativity by the examination about the arguments, unlike previous approaches. Finally, we study subjectivity, focus, event headness, goal which are characteristics of distinuishing double subject construction and dative subject construction. Especially, in the case of psychological and possesive adjectives, though double subject construction and dative subject construction are freely convertible, but by above semantic and aspectual characteristics, they appear to be distinguished in the surface.