Folk music, passed down by oral and aural tradition, did not possess sheet music, so it developed an accompaniment of suseonggarak (隨聲), which was instrumental improvisation by playing along main melodies of songs. By the necessity of preservation, transmission, and teaching materials, however, folk music is being educated in the sheet music form written by staff notation. This causes following problematic phenomena. The notation different from real notes is unable to present a right key for singing, and the recorded music sheet makes improvisational nature of suseonggarak as stereotyped. Since the suseonggarak accompaniment of Korean vocal music can show dynamics and cadence of jangdan while playing along melodies of songs, and its intro can suggest the main key, it is very effective for teaching singing skills. Therefore, the current study aims to provide basic learning materials for the accompaniment method of suseonggarak which enables one to accompany various Korean vocal music with gayageum. For this, it examines the traditional accompaniment methods of Korean vocal music such as gagok, gasa, sijo, pansori, byeongchang, folk songs, and etc. through literature and musical sources, and sorts out the accompaniment methods of suseonggarak based on lyrics, rhythmic patterns, and cadence. The findings include the performing techniques of naedeureum suggesting rhythmic patterns and main key of songs, placement of accents and accompaniment for highlighting hidden meaning of lyrics, the accompaniment method for vowel parts in a singing technique of eodanseongjang (語短聲張: consonants/words are pronounced short, while vowels/sound are pronounced long), and the accompaniment method for cadence. Finally, suseonggarak accompaniment method is proposed by applying these to accompaniment for pyeongsijo and folk songs.