As the central administrative government office, there were 9 Si (_??_) and 5 Jian (_??_) in the Tang (_??_), 9 Si (_??_) and 6 Jian (_??_) in the Song (_??_), 8 Si (_??_) and 7 Jian (_??_) in the South Office of the Liao (_??_), and 11 Yuan (_??_), 2 Si (_??_), 6 Jian (_??_) and 3 Si (_??_) in the Jin (_??_) dynasty.On the other hand, the Yuan (_??_) dynasty had 14 Yuan (_??_), 10 Si (_??_), 12 Jian (_??_), 3 Si (_??_) and 5 Fu (_??_), except Zhongshusheng (_??__??__??_) and Liubu (_??__??_).It becomes clear that there is an analogy among the institutions in the Tang (_??_), the Song (_??_) and the Liao (_??_) dynasty, and that the system in the Yuan (_??_) was built up under the influence of the Jin (_??_) dynasty.The followings are the special characters of Jian (_??_) in the Yuan (_??_) period.(1) It is very large in number.(2) The subordination among the offices is very much complicated.(3) It has, as a rule, the plural chief officers, and it has 8 chiefs at some offices.(4) Quite a number of the government officials worked in their offiices.(5) Generally, the official rank is very high, and the rank of the chief officer is the upper in no. 3 class.(6) The government organization was reformed frequently; the changing of the name, the ups and downs of the rank, and the separation and annexation of the office were held several times.(7) The number of the government men was often increased or decreased, too. These aforesaid special characters came from the next circumstances.(1) The Yuan (_??_) dynasty gave preferential treatment to the Mongolians, and the government system in this period introduced the Mongolians' own customs, such as the council system and the shift system.(2) The complicated subordination was due to the nomadic Mongolians' loose thought rather than to their incompetence.In short, the government system in the Yuan (_??_) dynasty is the fixed style of the military administration by the Mongolian conquerors.