This study examined changes in party-military relationship through power structure and succession process of the Kim Ilseong, Kim Jeongil and Kim Jeongeun regime, in order to clarify how Kim Jeongeun in North Korea has dominated and taken advantage of the party and the military, to seize and solidify his regime for the last six years, especially how status and roles of the party and the military have been transformed in the process. On the basis of the Manchrian party as a political foundation, Kim Ilseong established the North Korean Military before he took over the leadership, then the cult of personality around Kim Ilseong was emphasized within the Korean People's Army. He strengthened party register control for the military through the political committee system during the Korean War, and then, he eliminated counterforce by purging hard-liners and military authorities on the occasion of the factionalist incident, while maintaining and strengthening Suryeong's monolithic leadership, ‘party-state regime’ around Suryeong. Kim Jeongil as a successor gradually seized the party and the military based on the ‘Ten Principles for Party's Monolithic Ideological System’, through his fathers' power and authority. Above all, main consultative bodies and organizations which had played key roles in decision makings in ‘party-state regime’ could not properly function any more, whereas the power of Kim Jeongil was intensified and Military-First-Policy was institutionalized through decision-makings around the National Defense Committee. The party's function was restored by Kim Jeonguen in 2012, after the death of Kim Jeongil, but also the party register control for the military was strengthened, indicating that various measures were tried to institutionalize another type of ‘party-state regime’ by containing the Military-First-Policy'. After acceding to the ‘Chairman of the Labour Party’, the highest position of North Korea at the 7th convention of the party in June, 2016, Kim Jeongeun nominally and virtually restored the ‘Suryeong-directed regime’ or the party-based ‘party-state regime’, as he reorganized national organizations and became the ‘leader of state ministers’. However, it may be somewhat clumsy judgement that the restoration of party-military relationship led to stability of the regime or normalization of party-military relationship. First, the Military-First-Policy as a governing ideology during the era of Kim Jeongil, which aimed to overcome crises home and aborad was rooted in and complementary to the self-reliance ideology, rather than replaced it. Although military authorities's status and influences were reinforced and enlarged, compared to those of the party, chronic and serious degeneration of conventional military strength or economic problems in North Korea could not resolved even by the Military-First-Policy. Second, it was not certain that the military authorities whose roles and status were strengthened and enlarged by the Military-First-Policy kept their spontaneous loyalty for Kim Jeongeun's style of the reign of terror based on purges and elimination. The military authorities and their elites have experienced serious loss of their power and benefits, as the General Politburo and the Military State Security Agency monitored, controled and brutally purged them, especially their material basis including various interests and earning foreign currency was transferred ,and only the specific department responsible for nuclear weapons has been supported and resources have been concentrated on enhancement of people's life and economic construction, since the parallel pursuit of both economy and nuclear weapons was announced and conventional military strength was weakened, suggesting that it is difficult to ascertain if the military can secure normalization of party-military relationship and stability of the regime as before.