This article explores the theoretical roots of pentatonic chords in North Korean music practice. According to the literature review, the representative research results with a relatively logical system can be categorized into two theories (theory 1 and theory 2). Theory 1 primarily explains the principles and functions of national chords by elaborating on general principles and characteristics of multi-voice composition in folk music, the foundations and characteristics of multi-tone composition in folk five-tone mode and the structural characteristics of synthesized sounds, the characteristics of major second interval and complete fourth interval, pentatonic 3 chords and 4 chords and 5 chords, etc., based on the flat and interface-adjusted. Theory 2 mainly explains the rationality of the structure by elaborating on how the palace, quotient, angle, sign, feather tones which belong to the flat tone and the interface tone form the pentatonic 3, 4, 5 chords by concentrating on the main sound. The third chapter analyzes the practical application of pentatonic 3,4,5 chords and Western major and minor modulations in North Korean music works, and uses of the theory 1 and theory 2 to comprehensively reflect in the creation works. The conclusion section introduces the similarities and differences between the two theories. Although the theoretical basis for the function is not perfect, these two theories have their own unique academic insights. Compared to theory 2, theory 1’s research results are more logical and have established a more comprehensive system. Therefore in the practice of North Korean music, pentatonic chords with both functional and structural significance are organically integrated with Western major and minor modulations systems. This article analyzes the structural principles of the two theories and the application in music practice as well as testing the actual effects by creating works.