This essay devotes itself to answering the following questions: firstly, how does the department influence China's peacekeeping operation (PKO) policy in Xi Jinping's administration? Secondly, is the influence of the department in Hu Jintao's era similar to that under Xi? Thirdly, if the department is a dominant authority on PKO policy, would PKO policy be more inclined to its interest? Given the military department's preference, while the scale of PKO mission increases, the more troops Beijing will dispatch; however, while the casualty record in its mission becomes more severe, Beijing will decrease their personnel contribution. Secondly, while state-owned enterprises (SOEs) invest more in their host country, Beijing will also contribute more troops, but this effect occurs only on the condition that the mission scale and casualty record satisfies military's preferences. Finally, the analysis in this research indicates that parochial interest still influences China's policy under Xi, but the Chinese military is more influential than other departments.