The so-called "Kham area four big tusi" is specified, Ritang, Batang and Dege four tusi. Qing dynasty, the Kham region (now Sichuan Ganzi Prefecture) of the size of the Tusi 138, the four most powerful. This many of the Secretary for the court authorized, there is also a high and low official rank, but each does not belong to, and do not receive the court salary. The duties of the Secretary of the soil is each of its tribal, wartime "at the call of duty", usually "attached to the series of knot barbarians, carefully guard the territory, to prevent civil strife, to protect the territory of the people", and to the court in accordance with the regulations of the tribute to Na Fu. Tribute is the subjugation to the central dynasty, accept the tribute is a symbol of the power of the court, its main significance does not lie in the economic benefits, but to communicate with each other to strengthen the control of the central dynasty of the border areas. Most of the tributes of the Tusi are local products, mountain treasures, precious herbs, horses, cattle and livestock. The court accepts the tributes of the tributary, but also to be given back. The gift of gold and silver jewelry, silk, silk, tea, food, household goods and even production tools. From a historical point of view, the early implementation of this tribute and give back, for the promotion of the development of the Tibetan economy, to promote the improvement of living customs and mode of production, and to promote cultural exchanges, have certain positive significance.